Mr. Duggal invested Rs. 20000 with rate of interest @ 20 p.c.p.a. The interest…

Mr. Duggal invested Rs. 20000 with rate of interest @ 20 p.c.p.a. The interest was compounded half-yearly for the first year, and in the next year it was compounded yearly. What will be the total interest earned at the end of 2 years?