The simple interest on a sum for 5 years is one fourth of the sum. The rate of interest per annum is

In how much time will a sum of Rs. 12500 amounts to Rs. 20000 at the rate of 8 percent per annum at simple interest?

A sum of money doubles itself in 7 years at simple interest. In how much time will it become 5 times of itself?

A sum of money becomes Rs 16000 in 6 years at the rate of 25% per annum simple interest. What is the total interest for 6 years?

A sum of money at simple interest amounts to ₹ 1,012 in $$2{1\over2}\%$$ years and to ₹ 1,067.20 in 4 years. The rate of interest per annum is:

The simple interest on a certain sum at 15% per annum for 5 year is Rs1500 more to the simple interest on the same at 12% per annum for the same period. Find the sum-

 If 64 amount to 83.20 in 2 years what will ₹ 86 amount to in 4 years at the same rate percent per annum? 

Mahesh invests a sum of money which becomes Rs. 1344 in 3 years and Rs. 1536 in 7 years. How much had he invested?