In how many years will Rs. 7200 to Rs. 7938 at 10% per annum when compounded half-yearly.
The correct option is B: 1 year
Principal, P=Rs 7200
Amount, A=Rs. 7938
Rate, r=10% per annum
Time, t=?
When interest is compounded half- yearly
Rate @ half yearly =102
n= number of times interest added = number of half year
Amount, A=P(1+r100)n
7938=7200(1+5100)n
⇒79387200=(1+0.05)n
⇒39693600=(105100)n
⇒13231200=(105100)n
⇒441400=(105100)n
⇒(2120)2=(2120)n
∴n=2
when n= number of half year =2, time will be 1 complete year.