# Some people have interest in interest!!!

**Algebra**Level 3

An amount of Rs. 12820 due 3 years hence is fully repaid in three annual installments starting after 1 year. The first installment is 0.5 times the second one and the second one is 0.666 times the third one. If the rate of interest is 10% per annum, find the first installment (in Rs.).