Question

if a boy present age is 7 yr & his uncle present age is 31 after how many yr his uncle age was twice of his boy age

Answer 1

31+n = 2(7+n)

31 + n = 14 + 2 n
17 = n
so in 17 years

then check
7 + 17 = 24
31 + 17 = 48 sure enough twice 24