Question Detail

The total age of A and B is 12 years more than the total age of B and C. C is how many year younger than A

Answer: Option B

Explanation:

Given that A+B = 12 + B + C
=> A – C = 12 + B – B = 12
=> C is younger than A by 12 years

1. Average age of A and B is 24 years and average age of B, C and D is 22 years. The sum of the ages of A, B, C and D is

90
98
120
Data is not adequate

Answer: Option D

2. A man is 24 years older than his son. In two years, his age will be twice the age of his son. The present age of his son is

20 years
21 years
22 years
24 years

Answer: Option C

Explanation:

Let the son's present age be x years. Then, man's present age = (x + 24) years
=> (x + 24) + 2 = 2(x + 2)
=> x + 26 = 2x + 4
So, x = 22

3. The ages of two persons differ by 20 years. If 5 years ago, the elder one be 5 times as old as the younger one, their present ages (in years) are respectively

20,20
20,10
25,15
30,10

Answer: Option D

Explanation:

Let their ages be x and (x + 20) years.
5 (x - 5) = (x + 20 - 5) or 4x = 40 or x = 10.
Their present ages are 30 years and 10 years

4. Ratio of ages of three persons is 4:7:9, Eight years ago, the sum of their ages was 56. Find their present ages.

16,35,36
12,28,36
16,28,27
16,28,36

Answer: Option D

Explanation:

Let the present ages are 4x, 7x, 9x.
=> (4x-8) + (7x-8) + (9x-8) = 56
=> 20x = 80
=> x = 4

So their present ages are: 16,28,36

5. Tanya's grandfather was 8 times older to her 16 years ago. He would be 3 times of her age 8 years from now. What was ratio of ages of Tanya and her grandfather 8 years ago.

11:50
11:51
11:53
11:54

Answer: Option C

Explanation:

Let, Tanya age 16 years ago = x,
Grandfather's age 16 years ago = 8x.

8 years from now, 3(x+16+8) = (8x+16+8)
=> x = 48/5

8 years ago ratio was:

\begin{aligned}
=> \frac{x+8}{8x+8} = \frac{\frac{48}{5}+8}{8 \times \frac{48}{5}+8}
\end{aligned}

\begin{aligned}
=> \frac{88}{424} = \frac{11}{53}
\end{aligned}