A sum of money becomes 3 times in 12 years. In how many years it will become 5 times at the same rate of simple interest?

A person lends 40 % of his sum of money at 15 % per annum, 50 % of rest at 10 % per annum and the rest at 18 % per annum rate of interest. What would be the annual rate of interest, if the interest is calculated on the whole sum? 

A man invested Rs.25000 on simple interest at R% p.a. If interest received by man is three twentieth of the principal after three years, then find ‘R’?

The difference of simple interest from two banks on ₹8,000 in 3 years is ₹800. If the rate of interest per annum in two banks are R1 and R2, then what is the value of R1 - R2? (Where R1 > R2)

A sum of ₹ 400 amounts to ₹ 480 in 4 years. What will it amount to if the rate of interest is increased by 2 %? 

A certain amount of money earns Rs. 540 as simple interest in 3 years. If it earns a compound interest of Rs. 376.20 at the same rate of interest in 2 years, find the amount.

A person deposited ₹500 for 4 years and ₹ 600 for 3 years at the same rate of simple interest in a bank. Altogether he received ₹ 190 as interest. The rate of simple interest per annum was 

If the simple interest on a certain sum of money for 2 years in one fifth of the Principal, then find rate of interest per annum.