A sum of money at simple interest doubles in 7 years. It will become four times in: (a) 18 years    (b) 21 years    (c) 38 years    (d) 42 years

A sum of money at compound interest double itself in 15 years.It will become eight xx of itself in

A sum of money doubles itself in 7 years. In how many years it will become 4 times ?

A finance company declares that, at a certain compound interest rate, a sum of money deposited by anyone will become 8 times in 3 years. If the same amount is deposited at the same compound rate of interest, then in how many years will it become 16 times? (a) 4 years (b) 5 years (c) 6 years (d) 7 years

A sum of money invested at simple interest triples itself in 8 years. How many times will it become in 20 years time?

If a Sum of money doubles itself in 7 years, it becomes 5 times in how many years?