A man can buy a new house in 4 years with all of his earnings. But he spend the same amount in household expenses in 8 years and for savings in 12 years. How many time needed for buying the house?
Options:
(A) 12
(B) 20
(C) 30
(D) 15
(E) 24 OK. Let's think. Some random thoughts first:
His savings in 1 year = 1/4 - (1/8+ 1/12) = 1/24
He can buy a new house in 24 years The answer: (E).