A sum doubles itself in 4 years at simple interest. How many times will it amount in 8 years at the same rate of simple interest?

A sum of money becomes 3 times in 5 years at simple interest. In how many years will the same sum become 6 times at the same rate of simple interest?

A certain sum of money becomes three xx of itself in 20 years at simple interest.In how many years does it become double of itself at the same rate of simple interest?

A sum of money doubles itself in 4 years at compound Interest. It will amount to 8 times itself at the same rate of interest in :

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 ?

A certain sum of money becomes three times of itself in 20 yr at simple interest. In how many years, does it become double of itself at the same rate of simple interest ?

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?