[A].
[B].
[C].
[D].
Answer: Option B
Explanation:
Let the ages of father and son 10 years ago be 3x and x years respectively.
Then, (3x + 10) + 10 = 2[(x + 10) + 10]
3x + 20 = 2x + 40
x = 20.
Required ratio = (3x + 10) : (x + 10) = 70 : 30 = 7 : 3.
[B].
[C].
[D].
Answer: Option B
Explanation:
Let the ages of father and son 10 years ago be 3x and x years respectively.
Then, (3x + 10) + 10 = 2[(x + 10) + 10]
3x + 20 = 2x + 40
x = 20.
Required ratio = (3x + 10) : (x + 10) = 70 : 30 = 7 : 3.
[B].
[C].
[D].
Answer: Option C
Explanation:
Let the mother’s present age be x years.
| Then, the person’s present age = | 2 | x | years. | ||
| 5 |
| 2 | x + 8 | = | 1 | (x + 8) | |||
| 5 | 2 |
2(2x + 40) = 5(x + 8)
x = 40.
[B].
[C].
[D].
Answer: Option D
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
x = 22.
[B].
[C].
[D].
Answer: Option D
Explanation:
Let C’s age be x years. Then, B’s age = 2x years. A’s age = (2x + 2) years.
(2x + 2) + 2x + x = 27
5x = 25
x = 5.
Hence, B’s age = 2x = 10 years.
[B].
[C].
[D].
Answer: Option B
Explanation:
Let their present ages be 4x, 7x and 9x years respectively.
Then, (4x – 8) + (7x – 8) + (9x – 8) = 56
20x = 80
x = 4.
Their present ages are 4x = 16 years, 7x = 28 years and 9x = 36 years respectively.
[B].
[C].
[D].
Answer: Option A
Explanation:
Let the ages of Kunal and Sagar 6 years ago be 6x and 5x years respectively.
| Then, | (6x + 6) + 4 | = | 11 |
| (5x + 6) + 4 | 10 |
10(6x + 10) = 11(5x + 10)
5x = 10
x = 2.
Sagar’s present age = (5x + 6) = 16 years.
[B].
[C].
[D].
Answer: Option A
Explanation:
Let the present ages of Sameer and Anand be 5x years and 4x years respectively.
| Then, | 5x + 3 | = | 11 |
| 4x + 3 | 9 |
9(5x + 3) = 11(4x + 3)
45x + 27 = 44x + 33
45x – 44x = 33 – 27
x = 6.
Anand’s present age = 4x = 24 years.
[B].
[C].
[D].
Answer: Option B
Explanation:
Let the present ages of Arun and Deepak be 4x years and 3x years respectively. Then,
4x + 6 = 26 4x = 20
x = 5.
Deepak’s age = 3x = 15 years.
[B].
[C].
[D].
Answer: Option D
Explanation:
Let Rahul’s age be x years.
Then, Sachin’s age = (x – 7) years.
| x – 7 | = | 7 | |
| x | 9 |
9x – 63 = 7x
2x = 63
x = 31.5
Hence, Sachin’s age =(x – 7) = 24.5 years.
| 1 |
| 6 |
[B].
| 5 |
| 12 |
[C].
| 1 |
| 2 |
[D].
| 7 |
| 9 |
Answer: Option B
Explanation:
Clearly, n(S) = (6 x 6) = 36.
Let E = Event that the sum is a prime number.
| Then E | = { (1, 1), (1, 2), (1, 4), (1, 6), (2, 1), (2, 3), (2, 5), (3, 2), (3, 4), (4, 1), (4, 3), (5, 2), (5, 6), (6, 1), (6, 5) } |
n(E) = 15.
| P(E) = | n(E) | = | 15 | = | 5 | . |
| n(S) | 36 | 12 |