Given that, Govind borrows Rs. 18000 at 10% simple interest to invest at 10% compound interest returns.
To find out: Amount of money Govind gains in one year.
As per simple interest, amount at the end of one year (A)=P(1+TR100)
Here, P=Rs.18,000, R=10% and T=1 year
∴ A=18000(1+1×10100)
⇒18000×1110
∴ A=Rs. 19800
Hence, Govind will have to return Rs. 19800 after one year.
He invests the money he borrowed at 10% compound interest, compounded half-yearly. Hence, the rate will become half and the time period will be double.
∴ P=Rs. 18,000, R=5% and n=2
As per compound interest, amount at the end of one year =P(1+R100)n
=18000(1+5100)2
=18000(2120)2
=18000×441400
=Rs. 19845
Hence, the amount Govind will get after one year of investment is Rs. 19845.
So, amount gained by him in one year Rs. 19845−Rs. 19800=Rs. 45.
Hence, Govind gains Rs. 45 in one year.