A man gets a simple interest of Rs.500 on a certain principal at the rate of 5% p.a in two years. Find the compound interest the man will get on twice the principal in two years at the same rate.
Choose the correct choice from the following answers:  A) Rs.500  B) Rs.250  C) Rs.5012.50  D) Rs.5062.50  E) None of these.
Let the principal be Rs.P   S.I at 5% p.a in 8 years on Rs.P = Rs.500   (P)(8)(5)/100 = 500   P = 1250   C.I on Rs.2P i.e., Rs.2500 at 5% p.a in two years   =2500{ [1 + 5/100]2 - 1} = 2500{ 212 - 202 /202}   = 2500/400(441 - 400)   = 25/4(41) = 1025/4 = Rs.256.25   ANSWNone of these.R:None of these.
<result>E</result>
A man gets a simple interest of Rs.500 on a certain principal at the rate of 5% p.a in two years. Find the compound interest the man will get on twice the principal in two years at the same rate.