Know about simple equations

1. Kirthan S Holla
CSE, pesitm.

2. Consider eqn
a1x+b1y+c1=0 and a2x+b2y+c2=0
Soln:

3. A father is twice son’s age. His age 10
years hence, will be 3 times, son’s age
10 years ago. find their ages.....
F=2S
F+10=3(S-10)
S=40 and F=80

4. If x, y, z are consecutive –ve integers, and
if x>y>z which of following is +ve odd
integer.......
 xyz
 [x-y][y-z]
 x-yz
 x[y+z]
 x+y+z
[x-y][y-z] is +ve odd integer.

5. If x>1, which of following decreases as ‘x’
increases.....
 x2-10x
 x+1/x
 1/x+1
 None
3. 1/x+1

6. A child brought a dairy milk, 5*, perk, the
prices of which are in integers in
decreasing order. Each items costs at
least 9/-.Total cost is 30. how many 5*
can he purchase with amount required
to purchase 10 perks...
 d>f>p
 Min=9
 Let p=9 then f+d=21
 So f=10 and d=11
So nmbr of 5* can be 9.

7. Sum of ages of sonam and genelia is twice
the sum of ages 7 years ago. what is
product of their present ages if sum of
squares of their ages 7 years ago is
100...........
195 180 200 164
s2 +g2=100
So s=6 and g=8
So after 7 years their ages will be 13 and 15
So answer is 195