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:

What sum will amount to ₹ 7000 in 5 years at $$3{1\over3}\%$$ simple interest ? 

At some rate of simple interest, A lent ₹ 6,000 to B for 2 years and ₹ 1,500 to C for 4 years and received ₹ 9,00 as interest from both of them together. The rate of interest per annum was

A sum of money lent at simple interest amounts to ₹ 880 in 2 years and to ₹ 920 in 3 years. The sum of money (in rupees) is

A person lends 40% of his sum of money at 15% per annum, 50% of the 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 person deposited ₹400 for 2 years, ₹ 550 for 4 years and ₹ 1,200 for 6 years. He received a total simple interest of 1,020. The rate of interest per annum is