At what rate percent per annum simple interest will a sum of money triple itself in 25 years

The population of a town increases 10% every 3 years.  If the present population of the town is 72,600.   Then its population after 6 years is 

At what rate percent  compound interest will Rs.625 amount to Rs. 900 in 2 years?

A sum amounts to rs. 1352 in 2 years at 4% compound interest.  The sum is

A sum of amounts to Rs. 1352 in 2 years at 4% compound interest. The sum is

At what rate percent per annum simple interest will a sum double itself in 8 years 4 months.

If the discount is 10% an items bought for Rs.9 is prices at 

A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 854 in 4 years.  The sum is:

Calculate the amount on Rs. 4,000 at 8% per annum for 2 years 

If S.P of an article is 4/3 of C.P then the profit in the  transaction is