The petroleum producing area in the Rajasthan is spread over how many districts?

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

A man had ₹ 16,000, part of which he lent at 4% and the rest at 5% per annum simple interest. If the total interest received was 700 in one year, the money lent at 4% per annum was

The simple interest on ₹ 7,300 from 11 May, 1987 to 10 September, 1987 (both days included) at 5% per annum is-

Manoj deposited ₹ 29400 for 6 years at a simple interest. He got ₹ 4200 as interest after 6 years. The annual rate of interest was-

A person borrows 5,000 for 2 years at 4 % per annum simple interest. He immediately lends it to another person at $$6{1\over 4}\%  $$ per annum simple interest for 2 years. His gain in this transaction is 

In what time will ₹ 72 become ₹ 81 at $$6{1\over4}$$ % per annum simple interest?