A sum of money doubles itself at compound interest in 15 years. In how many years it  will become eight times?

2,40,000 is taken as loan for three years compounded annually at 12.5 % p.a. At the end of first year, the interest is revised to 12 % p.a. The total amount to be repaid at the end of third year is:

The sum of length, breadth and height of a cuboid is 25 cm. The length of its diagonal is 15 cm. Find the total surface area of the cuboid.

The difference between simple interest and compound interest on a certain sum at $$ 12{1\over2}$$ % for 3 years is Rs 125. Find the sum.

The compound interest on Rs. 6250 at 12% per annum for 1 year, compounded half-yearly is

Mr. Tiwari invested Rs.25000 in two fixed deposits X and Y offering compound interest at 6% per annum and 8% per annum, respectively. If the total amount of interest accrued in two years through both fixed deposits is Rs.3518, then the amount invested in scheme X is -

A sum of Rs. 2000 at 40% per annum compounded annually. Calculate the interest for the third year at compound interest.

The compound interest earned in two years at 8 % per annum is 3993.6 . What is the sum invested?