Gayathri invested a sum of Rs. 12,000 at 5% p.a. at compound interest. She received amount of Rs. 13,230 after ‘n’ years. Find the value of ‘n’.

Sujatha borrows Rs. 12,500 at 12% per annum for 3 years at simple interest and Radhika borrows the same amount for the same period at 10% per annum compounded annually. Who pays more interest and by how much?

What sum is invested for 11/2 years at the rate of 4% p.a. compounded half –yearly which amounts to Rs. 1,32,651?

At what rate percent compound interest per annum will Rs. 640 amounts to Rs. 774.40 in 2 years?

Find the rate percent per annum, if Rs. 2,000 amounts to Rs. 2,315.25 in an year and a half, interest being compounded half-yearly.