Mathematics questions

2. 1. If two dice are roll, what is the
probability of getting a sum of 13?
ans. 0(zero)
the highest possible sum we can get
when rollin 2 dice is 12.

3. 2. Which of the following number is divisible
by 2 and 3?
a. 562,543 c. 354,042
b. 176,326 d. 288,626
ans. C
A number is divisible by 2 if it is an even number
and divisible by 3 if the sum of all the digits of the
number is divisible by 3.

4. 3. The sum of three consecutive integers is
129, what is the value of the second integer?
ans. 43
Let x be the 1st integer
x+1 be the 2nd integer
x+2 be the 3rd integer
x + (x+1) + (x+2) = 129
3x+3=129
3x=129-3
3x=126
x=42
2nd integer = x+1
= 42 + 1
2nd integer = 43

5. 4. If the difference of two number is 5, and the
sum of the their squares is 35. What is the
product of the two numbers.
ans. 5
let x be the 1st number
y be the 2nd number
x-y=5
x2 + y2 = 35

6. x-y=5 x2 + y2 = 35
(x-y)2 = 52
x2 -2xy + y2 = 25
( x2 + y2) – 2xy = 25
35 -2xy = 25
35 – 25 = 2xy
10 = 2xy
5 = xy
xy = 5

7. 5. What is the last digit of 4^2012?
ans. 6
41 = 4
42 = 16
43 = 64
44 = 256
2012 / 2 = 1006

8. that’s all
Thank you!