A) 25 years | B) 26 years |

C) 20 years | D) can't be determined |

Explanation:

Since we know that the difference b/w the age of any two persons remains always constant, while the ratio of their ages gets changed as the time changes.

so, if the age of his child be x (presently)

Then the age of wife be x + 26 (presently)

Thus the total age = x + ( x + 26) = 32 [ 252-220 =32]

x = 3

The age of her child is 3 years and her self is 29 years. Hence her age at the time of the birth of her child was 26 years.

Actual average salary of 12 officers = 400

Total salary of 12 officers = 400 x 12 = 4800

Average of these 12 officers as a whole =60

Total salary of 12 officers as a whole = 60 x 12 = 720

The total salary of rest = 4800 - 720 = 4080

Difference in average of the rest of officers = 60 - 56 = 4

Rest of the officers =

Total number of employees = 1020 + 12 = 1032