# If certain sum is doubled in 8 years on simple interest :

If certain sum is doubled in 8 years on simple interest, in how many years will it be 4 times?

(a) 24 years

(b) 16 years

(c) 32 years

(d) 12 years

(a) 24 years

(b) 16 years

(c) 32 years

(d) 12 years