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Attempt Online Questions for Problems on Ages with Detailed Explanation for SBI PO, SBI Clerk, LIC AAO 2021 and NRA CET

Direction: Read the following question carefully and choose the right answer.
1
Present average of age of A and B is 6x – 15 years. Present average age of A, B and C is 4x + 6 years. If present age of B is 25% less than the present age of C and 20% more than the present age of A, then find the present age of A.
» Explain it
A
Sum of the present age of A and B = 2 × (6x – 15) = 12x – 30 years

Sum of the present age of A, B and C = 3 × (4x + 6) = 12x + 18 years

So, the present age of C = 12x + 18 – 12x + 30 = 48 years

Present age of B = 48 × 0.75 = 36 years

Present age of A =  36  = 30 years
1.2

Hence, option A is correct.
2
The age of Arjun is (x + 5) years. The ratio of the age of Arjun 2 years hence to the age of Draupadi 1 year before is 6 : 5 respectively. If Arjun is 4 years older than Draupadi, then find the age of Shubhadra whose age is 4 years less than the average age of Arjun and Draupadi taken together. 
» Explain it
C
Age of Arjun = (x + 5)

Since Arjun is 4 years older than Draupadi , so Age of Draupadi = (x + 1)

According to question,

(x + 5) + 2  =  6
(x + 1) – 1 5

5x + 35 = 6x

x = 35

So, age of Arjun and Draupadi is (35 + 5) = 40 years and (35 + 1) = 36 years respectively

Average age of Arjun and Draupadi =  40 + 36  = 38 years
2

Therefore, age of Shubhadra = (38 – 4) = 34 years

Hence, option C is correct.
3
Arun and Meena recently celebrated their golden anniversary and their daughter Seema’s birthday. If the age of Seema 18 years after her parents’ marriage and her age at their golden anniversary is in the ratio 5 : 21, how many years after the marriage was Seema born?
» Explain it
A
Let the age of seema at their silver anniversary = K yrs

18 yrs of marriage = 7 yrs before silver anniversary

Age of seema 7yrs before silver anniversary = K – 7

Seema’S age 25 yrs after silver anniversary (golden anniversary) = K + 25

K – 7  =  5
K + 25 21

K = 17yrs

Seema’s age on silver anniversary = 17yrs

She is born 25 – 17 yrs = 8yrs after the marriage.



Hence, option A is correct.


Alternate Solution:-

Let the age of Seema 18 years after her parents marriage be 5k years

So age of Seema at golden anniversary of her parents = (5k + 32) years

From the question,

5k / (5k + 32) = 5 / 21

or, k =2 

So Seema's age was 10 ,  when her parents had completed 18 years of marriage.

So Seema was born 8 years after her parents marriage.

Hence, option A is correct.
4
Seven years later from now A will be as old as B was 4 years ago. C was born 2 years ago. The average age of A, B and C 10 years later will be 33yrs. What is the present age of A? 
» Explain it
B
Let age of A 7 years later be k so age of B 4 years ago was k
 
C was born 2 years ago so age of C 10 yrs later will be 12 years

  4 years ago Present 7 years later 10 years later
A k – 11 k – 7 k K + 3
B k K + 4 K + 11 K + 14
C   2 9 12

Average age of all three 10 yrs later = 33

K + 3 + k + 14 + 12  = 33
3

2k + 29 = 99 → 2k = 70 → k = 35

Present age of A = k – 7 = 35 – 7 = 28 years

Hence, option B is correct.
5
P’s age 8 years ago is equal to the sum of the present ages of his son and his daughter. 5 years hence, the ratio between his daughter’s age and his son’s age will be 7 : 6 respectively. P’s wife is 7 years elder than him. His wife’s present age is thrice the present age of his son. What is his daughter’s present age?
» Explain it
C
Let 5 years hence the age of daughter and son be 7x years and 6x years respectively, then
 
Present age of daughter= (7x – 5) years
 
Present age of son = (6x – 5)years
 
⇒ Present age of P = [(7x – 5) + (6x – 5) + 8] = (13x – 2)years
 
∴ Present age of P's wife = [(13x – 2) + 7] = (13x + 5) years
 
Given, present age of P's wife is thrice the present age of his son. 
 
(13x + 5) = 3(6x – 5)
 
⇒ x = 4
 
Hence, his daughter’s present age = (7x – 5) = 23 years.
 
Hence, option C is correct.