A certain sum quadruples in 3 years at compound interest, interest being compounded annually. In how may years will it become 64 times itself ?

A certain sum triples in 4 years at compound interest, interest being compounded annually. In how many years would it become 27 times itself ?

A sum becomes 5 times of itself in 3 years at compound interest (interest is compounded annually). In how many years will the sum becomes 125 times of itself?

A sum becomes 8 times of itself in 7 years at the rate of compound interest (interest is compounded annually). In how many years will the sum becomes 4096 times of itself?

A sum of money becomes four times itself in 5 years at a certain rate of interest, compounded annually. In how many years will it become 16 times itself at the same rate of interest?

A sum of money triples itself in 3 years at compound interest. In how many years will it become 9 times itself ?

A sum of money becomes 3 times in 10 years at the rate of compound interest (compounded annually). In how many years will it become 81 times?