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

A certain sum of money triples itself in 6 years at compound interest. In how many years will it become 27 times at the same rate of compound interest?

A certain sum becomes 3 times itself in 4 years at compound interest. In how many years does it become 27 times itself ?

A certain sum becomes 3 times itself in 6 years at simple interest. In how many years will it become 9 times itself ?

A sum of money becomes 3 times of itself in 6 years at compound interest. In how many years will it become 81 times?

A sum of money doubles itself at compound interest in 4 years. In how many years will it become 8 times?

If certain sum becomes 3 times itself in 4 years at compound interest, in how many years will the sum become 81 times itself at the same rate of interest?

A sum of money invested at simple interest triples itself in 8 years at simple interest. Find in how many years will it become 8 times itself at the same rate?

a. A sum of money doubles itself in 4 years at a certain rate of interest. In how many years will it triple itself at the same rate of interest ? b. A sum of money trebles itself in 6 years at a certain rate of interest. In how many years will it become four times itself at the same rate of interest ?