1. 1
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CHAPTER – 1
AVERAGE
Average Formulae: - Add up all the numbers, than divide by how many numbers there are.
Sum of observations
Average
Number of observations
Find the average speed
If a person travels a distance at a speed of x Km/hr and the same distance at a
speed of y km/hr then the average speed during the whole journey is given by:-
2xy
x y
If a person covers A km at x km/hr and B km at y km/hr and C km at z km/hr, then the
average speed in covering the whole distance is:
A B C
A B c
x y z
When a person leaves the group and another person joins the group in place of that
person then-
o If the average age is increased,
Age of new person = age of separated present + (increase in avg. x total no. of
persons)
o If the average age is decreased.
Age of new person = age of separated person - (decreases in avg. x total no of
persons).
o When a person joins the group – in case of increase in avg.
Age of new member = previous average + (increase in avg. x number of members
including new members).
o In case of decrease in average
Age of new members = previous avg. – (decrease in avg. x number of members
including new member).
When the number of terms is odd, the average will be the middle term.
When the number of terms is even the Avg. will be the avg. of two middle terms.
Arithmetic Progression:- a, a + d, a + 2d, a + 3d,…………..
2. 2
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First term = a
Difference = d
nth
term = �� = a +(n-1) x d
Sum of ‘n’ terms
2
n
Sn [2a + (n-1) x d]
Sum of first ‘n’ natural numbers
(1+2+3+--------+n) = ½ n(n+1)
Sum of ‘n’ odd no.
+ + 5 + ⋯ … … + � − = n2
' 'sum of n even no
(2+4+6+…………+2n) = n (n+1)
= sum of first squares of ‘n’ natural no.
2 2 2 2 1 1
(1 2 3 .........t ) x x ( 1)x(2 1)
6 6
n n n n n
Sum of first cubic of ‘n’ natural no.
3 3 3 1
(1 2 .........t ) ( 1)}.
2
n n n
****##****
3. 3
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CHAPTER-2
COMPOUND INTEREST
Compound Interest:- Where interest is calculated on both the amount borrowed and any
previous interest. Usually calculated one or more times per year.
formulae:-
When The Interest is compounded annually
Amount after ‘n’ years = A = P(1 )
100
nR
Compound interest = 4
(1 ) [(1 ) 1]
100 100
nR R
p p p
If P = principal
R = rate percent
Time = number of years
C. I = compound interest
A = amount
If the rate of interest differs from year to year i.e. R, in the first year, R2 in the second year,
R3 in the third year, Then,
31 2
(1 )(1 )(1 )
100 100 100
RR R
A
When the principal changes every year, we say the interest is compound annually. Then,
(1 )
100
nR
A P
When the principal changes as per every six months we say that the interest is
compounded half yearly or semi – annually. Then,
22(1 )
100
n
R
A P
- Quarterly
44(1 )
100
n
R
A P
****##****
4. 4
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CHAPTER – 3
SIMPLE INTEREST
SIMPLE INTEREST:- Define:- simple interest is interest paid any the original principal not
on the interest accrued.
Formula:-
P X R X T
.
100
S I
S.I – Simple Interest
R = Rate percent
T = Time in years
5. 5
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CHAPTER – 4
BOAT AND STREAM
Boat and Stream
Formulae:-
If the boat speed is x km/h in downstream y km/h in upstream, then
Speed of boat in still water is
( )
2
x y
speed of stream =
( )
2
x y
If speed of boat is x km/h and speed of stream is y km/h, then
Boat speed in downstream = x + y km/hr
(both speeds are added)
Boat speed in upstream = x-y km/hr
(y is subtracted from x)
Because boat speed is in opposite direction to speed of stream).
If the speed of boat or person in still water is x and speed of stream is y and the boat has to
cover a distance ‘d’ km Then time taken in down stream 1
tan
( )
( )
d dis ce
T Time
x y speed
Time taken in upstream 2
( )
d
T
x y
Total time taken in going down stream and upstream 1 2 [ ]
d d
T T T
x y x y
***##****
6. 6
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CHAPTER – 5
H.C.F AND L.C.M
H.C.F and L.C.M:- Highest common factor and lowest common factor
Formulae:-
When solving H.C.F and L.C.M questions with fractions These formulas are very helpful
1.
. .
. .
. .
H C F of Numerators
H C F
L C M of Numerators
2.
. .
. .
. . Denanenators
L C M of Numerators
L C M
H C F of
3. Product of two numbers:- Product of two numbers = product of their H.C.F and L.C.M
7. 7
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CHAPTER – 6
TIME AND DISTANCE
tanDis ce
Speed
Time
Conversion of km/hr to m/s
1 kmph =
5
18
m/s
Conversion of m/s to km/hr
1 m/s =
18
5
km/hr
If the ratio of speed of train A and B is a : b, then the ratio of time taken by them to cover
the same distance = b : a.
If a man covers a certain distance at x km/hr and an equal distance at y km/hr. Then the
avg. speed during the whole journey is.
2
/
( )
xy
km h
x y
The time taken by a train in passing a pole or standing man is the same as the time
taken by the train to cover a distance equal to its own length
The time taken by a train of length ‘L’ meters in passing a stationary object of length ‘B’
meters is equal (L+B) m.
If two trains are moving in the same direction at U m/s and V m/s where U>V, then their
relative speed will be equal to the difference of their speeds (U-V) m/s.
If two trains are moving in the opposite direction at um/s and Vm/s then their relative
speed will be equal to the sum of their speed (U+V) m/s.
If two trains of length ‘a’ meters and ‘b’ meters and moving in the same directions at U
m/s and Vm/s respectively, then
The time taken by the faster train to cross the slower train is:-
(a + b) / (u-v) sec.
If two trains of length ‘a’ meters and ‘b’ meters are moving in the opposite direction at U
m/s and V m/s respectively, then the time taken by the faster train to cross the slower
train is
a b
u v
sec.
8. 8
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CHAPTER – 7
PERMUTATION AND COMBINATION
Formulae:
1. Factorial Notation:-
Let ‘n’ be the positive integer. Then, factorial n, dented n: is defined as:
Factorial n, denoted n: is defined as:
1
0 ( 1)( 2).........3. 2. 1n n n n
2. Number of Permutations:-
Number of all permutations of ‘n’ things, taken r at a time, is given by :
1
0
1
0
P ( 1)( 2)..........( 1)
( )
n
r
n
n n n n r
n r
3. Permutation: - The different arrangements of a given no. of things by taking some or all
at a time, are called permutations.
4. Combination:- Each of the different groups or selections which can be formed by taking
some or all of a number of objects is called combination.
5. Number of Combination:-
The number of all combinations of ‘n’ things,
Taken r at a time is:-
1
0
1
0( 1)( )
n
r
n
C
r n r
9. 9
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CHAPTER – 8
TIME AND WORK
Formulae:-
1. Work from days:
If A can do a piece of work in ‘n’ days, then A’s 1 day’s work =
1
n
2. Days from work:
If A’s 1 day’s work =
1
n
Two A can finish the work in n day.
3. Ratio:
If A is Thrice as good a work man as then, Ration of work done by A due B = 3 : 1
Ration of times taken by A and B to finish a work = 1 : 3.
10. 10
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CHAPTER – 9
PIPES AND CISTERN
Inlet:- A pipe connected with a tank or a cistern or a reservoir, that tills it, is known as an
inlet.
Outlet:- 1. A pipe connected with a tank or a cistern or a reservoir, emptying it, is known as
an outlet.
1) if a pipe can fill a tank in x hours, two; part filled in 1 hour
1
x
2) if a pipe can empty a tank in y hours, then: part emptied in 1 hour
1
y
3) if a pipe can fill a tank in ‘x’ hours and another pipe can empty the full tank in y hours
(where y>x), then an opening both the pipes, then the net part filled in 1 hour =
1 1
( )
x y
4) if a pipe can fill a tank in x hours and another pipe can empty the full tank in y hours
where (x > y), then an opening both the pipes, then the net part emptied in 1 hour
1 1
( )
y x
11. 11
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CHAPTER – 10
MIXTURE AND ALLEGATION
Mixture and Allegation:-
1. Allegation:- it is the rule that enables us to find the ratio in which two or more
ingredients at two given price must be mixed to produce a mixture of desired price.
2. Mean Price:- The cost of a unit quantity of the mixture is called the mean price.
3. Rule of allegation:-
It two ingredients are mixed, then
. Pr
( )=( )
Pr .
Quantity of Cheaper C P of dearer Mean ice
Quantity of dearer Mean ice C P of Cheap
We present as under:-
.
( )
E P of a unit Quantity
c
.
( )
E P of unit Quantity
of dearer d
C.P of a unit quantity Mean price
(m)
(Cheaper Quantity) : (Dearer Quantity) ( )d m ( )m c
= (d-m) : (m-c).
4. Suppose a Container Contains x of liquid from which y units are taken out an replaced by
water.
After ‘n ’ operations, the Quantity of pure liquid = (1 )ny
x
x
units.
12. 12
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CHAPTER – 11
PARTNERSHIP
Partnership:- When two or more than two persons runs a business jointly, They are called
partners and the deal is known as partnership.
1. Ration of Divisions of Gains:-
(i) When investments of all the partners are for the same time, the gain or loss is
distributed among the partners in the ration of their investments.
Suppose A and B invest Rs x and Rs. Respectively for a year in a business, then
at the end of the year.
(A’s share of Profit) : (B’s share of profit) = x:y
(ii) When investments are for different time period then equivalent capitals are
calculated for a unit of time by taking (capital x number of units of time). Now gain
or loss is divided in the ratio of these capitals suppose A invests Rs x for p
months then, B (A’s share of forfeit) : (B’s share of profit) = x p : y q.
13. 13
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CHAPTER – 12
NUMBER SYSTEM:-
Formulas:-
1. 11,2,3..........O a are called digits.
2. 10, 11, 12,……….are called number.
3. Natural number (N):- Counting numbers are called natural numbers.
Ex:- 1, 2, 3,…………..etc. are all natural numbers, minimum natural number 1 and
maximum ∞.
Whole numbers:- if W is the set of whole numbers, then we write = {0, 1, 2,……….} The
smallest whole number 0.
Integer:- if I is the set of integers, then we write I = {-3, -2, -1, 0, 1, 2, 3………}
Rational No. – Any number which can be expressed in the form of plq. When p and q are
both integers and g o are called rational numbers.
E. g. =
3 7
, ,5, 2
2 9
There exists infinite number of rational number between any two rational numbers.
Irrational numbers:- Non-recurring and non-termination decimals are called irrational
numbers. These number cannot be expressed in the form of
p
q
.
E.g. = 3, 5, 29..........
Real numbers:- Real numbers include both rational and irrational numbers.
In General the number of n digit number are 1
9 10n
X
Sum of first ‘n’ natural numbers
1 +2+ 3+ ……..+n
( 1)
2
n n
Sum of the squares of the first n natural no 2 2 2 2 ( 1)(2 1)
1 2 3 ..........
6
n n n
n
Sum of cube of the first n natural numbers –
14. 14
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2
3 3 3 3 ( 1)
1 2 3 ..........
2
n n
n
Rules of divisibility:-
Divisibility by 2: A number is divisible by 2 when the digit at ones place is 0, 2 4, 6 or 8.
Eg:- 3582, 460,……….
Is divisibity by 3:- A number is divisible by 3 when sum of all digits of a number is
divisible by 3.
Eg:- 435 = 4+5+3=12
12 is divisible by 3. So, 435 is also divisible by 3.
Divisibility by 5: A number is divisible by 5 if its last digit is 0 or 5.
Eg:- 10, 25, 60.
Divisibility by 6: A number is divisible by 6, if it is divisible by both 2 and 3.
48, 24, 108.
Divisibility by 7:- A number is divisible by 7 when the difference between twice the digit
at ones place and the number formed by other digits is either zero or divisible by 7.
Eg:- 658.
65-2 X 8 = 65 – 16 = 49
As 49 is divisible by 7 the number 658 is also divisible by 7
Divisibility by 8:- A number is divisible by 8.
If a number formed by the last 3 digits of the number is divisible by 8.
Eg:- if we take the number 57832. The last three digits form 832. Since, the number 832
is divisible by 8. The number 57832 is also divisible by 8.
Divisibility by 9: A number is divisible by if the sum if all the digits of number is divisible
by 9. Eg: - 6 & 4 = 6+8+4=18
If is divisible by 9 so, 684 is also divisible by 9.
Divisibility by 10:- A number is divisible by 10, if its last digit is o eg. 20, 180, 350,
Divisibility by 11:- A number is divisible by 11. When the diffevncle between the sum of
its digits in odd places and in even places is either O or divisible by 11
30426
3+4+6=13
0+2=2
13-2=11
As the difference is divisible by 11 the numbers 30426 is also divisible by 11.
Division on numbers:-
In a sum of division, we have four quantities:-
They are (i) dividend (ii) Divisor (iii) Quotient (iv) Remainder
Relation:-
(a) Dividend = Divisor X Quotient + Remainder
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(b) Divisor = (Dividend – Remainder) Quotient
(c) Quotient = (Dividend – Remainder) Divisor
16. 16
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CHAPTER – 13
SERIES:
Series:
Arithmetic Sequence:- if a sequence of values follows a pattern of adding a fixed amount
from are term to the next, it is referred to as an aritumatic sequence. The number is added to
each term is constant.
Formula:-
To find any term of an aritumatic sequence 1 ( 1) xna a n d
To find the sum of a certain number of tens of an arithmatic sequences:-
1( )
2
n
n
n a a
S
, Where nS is the sum of in terms ( th
n Partial sum) 1a is the first term, na is
the th
n term
17. 17
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CHAPTER – 14
RATIO AND PROPORTION
What is Ratio:- A ratio is a relations ship between two numbers by division of the same
kind. The ration of a or b is written as a : b = a/b, in ratio a : b, we can say that a as the first
term or antecedent and b the second term or consequent
What is Proportion: - The idea of proportions is that two ration are like equal.
If a : b : = c : d, we write a : b : : c : d
Ex:-
3 1
15 5
A and d called extremes, where as b and C called mean terms.
Proportion of Quantities:-
The four quantities like a, b, c, d we can express in a : b = c : d
Tune a : b : : c : d = (a x d) = (b x c)
If there is given three quantities like a, d, c of same like then we can say it proportion of
continued.
a : d = d : c, d is called mean term,
a and c are called extremes.
18. 18
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CHAPTER-15
PROBLEMS ON AGES:-
1. If the current age is x, the ‘n’ times the age is nx.
2. If the current age is x, then age n years / later = x + n
3. If the current age is x, then age n years ago = x – n
4. The ages in a ratio a : b will be a x and b x
5. If two current age is x, then
1
x
of the age is
x
n
19. 19
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CHAPTER – 16
ALGEBRA
Basic algebra:- One should be well versed in basics of algebra.
Certainly, we should know about same questions based an equations and their roots.
Polynomials:- An expression in terms of same variables is called polynomial.
For e.g.:- ( ) 2 5f x n is a polynomial in variable x.
2
( ) 5 3 4g y y y is a polynomial in viable
The expression f (x) =
1
2
1 1 0.......
n
x
nanx a a x a
is called a polynomial in variable x
where n be a positive integer and 0 1............,a a be constants.
Degree of a poly nominal:-
The exponents of the highest degree term in a polynomial is known as its degree.
Linear polynomial:-
A polynomial of degree one is called a linear polynomials In general f (x) = a x + b, where
1
a o is a linear polynomial.
Quadratic Polynomial:- A polynomial of degree two is called a quadratic polynomials., In
general
2
,ax bx c where 1
a ois a Quadratic polynomial.
Cubic Polynomial:- A polynomial of degree 3 is called a cubic polynomial in general.
3 2 1
( ) 9 ( )f x x bx x d a o is a cubic polynomial
Remainder Theorem:- Let f (x) be a polynomial of a degree greater than or equal to are and
a be any real number, if f(x) is divisible by (x-a), then the remainder is equal to f (a).
Factor Theorem:- Let f(x) be a polynomial of degree greater than or equal to one and a be
any real number such that f(a)=0, then (x-a) is a factor of f (x).
Useful formulae:-
1)
2 2 2
( ) 2x y x y xy
2)
2 2 2
( ) 2x y x y xy
3)
2 2
( ) ( )( )x y x y x y
4)
3 3 3
( ) 3 ( )x y x y xy x y
5)
3 3 3
( ) 3 ( )x y x y xy x y
6)
3 3 2 2
( ) ( ) ( )x y x y x y xy
7)
3 3 2 2
( ) ( ) ( )x y x y x y xy
8)
2 2 2 2
( ) 2( 3 )x y z x y z xy yz x
9)
3 3 3 2 2 2
( 3 ) ( )( )x y z xyz x y z x y z xy yz zx
20. 20
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10) If 0,x y z then
3 3 3
3 ....x y z xyz
21. 21
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CHAPTER – 17
PROFIT AND LOSS
Cost Price:- The price, at which an article is purchased, is called its cost price, abbreviate
as C.P.
Selling Price:- The price, at which an article is sold, is called its selling Prices, abbreviated
as S.P.
Profit or Gain:
If S.P. is greater than C.P, the seller is said to have a profit or gain.
Loss:- If S.P. is less than C.P, the seller is said to have incurred a loss.
Important formulae:-
1. Gain = (S.P) – (C.P)
2. Loss = (C.P) – (S.P)
3. Loss or gain is always reckoned an C.P
4. Gain% =
x 100
( )
.
Gain
C P
5. Loss%=
x 100
( )
.
Loss
C P
6. Selling Price:-
(100 %)
. [ x . ]
100
Gain
S P C P
7. Selling Price:-
(100 %)
. [ x . ]
100
Loss
S P C P
Cost Price (C.P)
8. Cost Price (C.P)
100
. [ x . ]
(100 %)
C P S P
Gain
9. Cost Price (I.P)
100
. [ x . ]
(100 %)
C P S P
Loss
10. When a person sells two similar items, one at a gain at say x%, and the o three at a loss
of x%, then free seller always incurs a loss given by:
2 2& %
%( ) ( )
10 10
Common Loss and Grain x
Loss
11. If a trader professor to sell his goods at C.P, but uses false weights, then
% ( x100)%
( ) ( )
Error
Gain
True value error
22. 22
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CHAPTER – 18
DISCOUNT
Formula:-
Discount = List price – selling price
Selling price = list price – discount
Selling price = list price – discount
List price = selling price + discount
Rate of discount = discount % x100
Pr
Discount
List ice
List price = selling Price x
100
(100 %)discount
Selling price = list price x
(100)
=
(100-discount%)
23. 23
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CHAPTER – 19
MENSURATION
It Cautions L- Parts:-
2-D- 2 dimensional figures.
1. Square:- ‘a’ is side of a square all side are equal
Area = 2
a
Perimeter = 4 a
Diagonal = 2a
2
2
2
d
a
2. Rectangle:-
Opposite sides are equal.
Area = l x b
L = length
B= breadth
Perimeter = 2 (l + b)
3. A equilateral triangle:-
All sides are equal.
Area =
2
3
4
a
Perimeter = 3a
3
2
xa
- height
Isosceles triangle and Right angled triangle:-
B= base
H= height
The, Area =
1
2
x b x h
4. Scalene triangle:- All sides are different to each outer.
C semi perimeter:-
2
a b c
S
Area = ( )( )( )s s a s b s c
5. Area of Triangle-
1
x
2
D X base height
24. 24
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( )( )( )s s a s b s c
is is perimeter.
4
abc
D
R
R = Circumradius
D= r x s
r= inradius, s = remiperimeter
1 1 1
sin sin sin
2 2 2
D ab bc ab
6. Parallelogram:- Area = sinab
= 2 (a+b)
Area = b x h
Area = a x h
7. Rhombus:- Parameter:- 4 a
Area = 1 2
1
x x
2
d d
2 2
1 2
1
2
a d d
1d and 2d are two diagonals in Rhombus – both diagonals cut at 0
90
8.Trapezium:-
Area =
1
2
(sum of parallel sides) x altitude
Area =
1
2
x (a + b) x h
H= height
A, b are two parallel sides
9. Hexagon:-
Hexagon have sex sides and if cautions six equilateral triangles.
So, the area = 23
6x x
4
a
25. 25
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Because the area of an equilateral triangle perimeter = 6 a
10. 3 – D = 3 dimensional figures:-
Prism Pyramid Sphere
Cylinder Cone Hemisphere
Cube Other base
Cuboid Pyramid
Outer base prism frustum
Tetrahedral
11. Prism:- Surface area:- Perimeter of base x height
Pyramid – Surface area =
1
x
2
Parimeter of base x slant height
Volume =
1
x
3
Area of base x height
12. Cuboid:-
6 – faces
8 – corner
12 – edges
Vol. – l x b x h
Diagonal =
2 2 2
l b h
Curved Surface area = 2 (bh + hl)
Total surface area = C.S.A + 2 lb
2 (lb + bh + hl)
We are not count the base and Top in curved surface area a
13. Cube:- Volume =
3
a
Diagonal = 3a
Total Surface area = 2
6a
Cylinder:-
Vol:- 2
r h
Curved surface area = 2 xTTr h
2
. . . . 2T S A C S A r
2
2 2rh r
2 ( )r r h
26. 26
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14. Cone:-
2 2
l r h
Slant height.
Vol:- 21
x
3
r h
C.S.A = rl
2
. .T S A rl r
( )r r l
15. Sphere:- Vol:-
34
3
r
2
. . 4C S A r
16. Hemisphere – Vol: -
32
3
r
2
. . 3C S A r
17. Frustum of a cone:-
Vol:- 2 2
x (R )
3
h
r Rr
2 2 2
= h ( )l R r
Curved Surface area = l (R + r)
Total Surface area:- (area of the base) + (area of the Top) + (curved surface area)
=
2 2
{ ( )}R r l R r
=
2 2
[ ( )]R r l R r
18. Probability:- it’s a possibility of any towing.
Probability =
l n .
Number of favourable out comes
Tota o of out comes
If tossed a coin, then we have two possibility either head or tail.
2-possibilities
If we tossed two coins times then Possibility {TH, HT, HH, TT}
****##****