8. X is two years older than Y who is twice as old as Z. The total of the ages of X, Y and Z is 27 . How old is Y?
A. 10
B. 9
C. 7
D. 8

Explanation:
A=2+B
B=2C
A+B+C=27
A=12,B=10,C=5

B=10

9.The average age of a class of 22 students is 21 years. The average increased by 1 when the teacher's age also included. What is the age of the teacher?
A. 48
B. 45
C. 44
D. 43

Explanation:
Total age of students =22×21
Total age of students + age of teacher =23×22
Age of the teacher=23×22−22×21
=22(23−21)=22×2

=44

10. The sum of ages of 4 children born at the intervals of 3 years each is 38 years. Find out the age of the youngest child?
A. 5 years
B. 6 years
C. 4 years
D. 3 years

Explanation:
let the age of the youngest son be Y
Y+(Y+3)+(Y+6)+(Y+9)=38

Y=5

11.A father said to his son, "I was as old as you are at the present at the time of your birth". If the father's age is 38 years now, what was the son's age five years back?
A. 18 years
B. 14 years
C. 22 years
D. 20 years

Explanation:

Let Father's present age be F
Let son's present age be S
F=38
38-S=S
S=19

S-5=14

12. Virat's age is 1 / 6 th of her father's age. Virat's father's age will be twice Padikal's age after 10 years. If Padikals's eight birthdays was celebrated two years before, then what is Virat's present age.
A. 10
B. 12
C. 5
D. 8

Explanation:
let Virat's age be V
Let Father's age be F