If , then the value of a+b is equal to:

Atm of ₹2.400. amounts to ₹3,264 in 4 years at a certain rate of simple interest. If the rate of interest is increased by 1% the same sum in the same time would amount to-

The amount ₹2,100 became ₹ 2,352 in 2 years at simple interest. If the interest rate is decreased by 1%, what is the new interest?

Mohan lent some amount of money at 9% simple interest and an equal amount of money at 10% simple interest each for two years. If his total interest was Rs. 760, what amount was lent in each case?

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