Age of A = (3/8) x 56 = 21 yr
Age of B = (5/8) x 56 = 35 yr

Correct Option: C

Age of A = (3/8) x 56 = 21 yr
Age of B = (5/8) x 56 = 35 yr
Before 7yr, ration of the ages of A and B
= (21 - 7) : (35 - 7)
= 14 : 28
= 1 : 2

Let the age of father = 5k
and the age of son = 2k
According to the question,
5k x 2k = 1000

Correct Option: B

Let the age of father = 5k
and the age of son = 2k
According to the question,
5k x 2k = 1000
⇒ 10k² = 1000
⇒ k² = 100
∴ k = √100 = 10
∴ Father's age after 10 yr = (5k + 10)
= 5 x 10 + 10
= 60 yr

Let first number is P and second number is Q.
Then, according to the question,
P x 35% = 2 x Q x 75%
⇒ (P x 35)/100 = (2 x Q x 75)/100

Correct Option: E

Let first number is P and second number is Q.
Then, according to the question,
P x 35% = 2 x Q x 75%
⇒ (P x 35)/100 = (2 x Q x 75)/100
⇒ P/Q = (2 x 75)/35 = (2 x 15)/7 = 30/7
∴ P : Q = 30 : 7

Since (3x – 7 ) : (4x + 3) is the sub -triplicate ratio of 8 : 27,
therefore ,

Correct Option: D

Since (3x – 7 ) : (4x + 3) is the sub -triplicate ratio of 8 : 27,
therefore ,

Let the third proportional be x . Since the third proportional to 9 and 27 is the same as fourth proportional to 9,27,27
∴  9 : 27 : : 27 : x

Correct Option: D

Let the third proportional be x . Since the third proportional to 9 and 27 is the same as fourth proportional to 9,27,27
∴  9 : 27 : : 27 : x