[administration]

Q. A grandmother’s age is in between 50-70 year. She had some son, each son had as many son as he had brothers.Grandmother’s age was as many grandson in family. Find the grandmother’s age?

A)52 B)55 C) 56 D)59

[administration]

Let grandmother has x sons

so each son has x-1 brothers and hence x-1 grandsons.

so total number of grandsons = x(x-1)

 

also since grandmother’s age is in between 50-60 .

so 50< x(x-1) <60 which is satisfied by x=8  and no other natural number
Hence grandmother’s age = 8×7 = 56

[Author]

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