Find the compound Interest on Rs. 8,000 @15 % p.a for 2

Solution

C.I for 1 st year = (8000 × 15 × 1)/100 =1200 C.I for 2nd year  = (9200 × 15 × 1)/100 = 1380 C.I for 1/3 year = (10580 × 15 × 1)/(100 × 3) = 529 Total C. I = 1200 + 1380 + 529 = Rs. 3109 Alternate Method ; If time is given in ratio (a +  1/b) years, then {Amount = Principal(1+ R/100)^a  (1+R/100  × 1/b)}  Here a= 2 & b =3 A= 8000 (1+15/100)² (1+15/100×1/3) = 8000 × 23/20 × 23/20 × 21/20 = 11109 C.I = 11109 - 8000 C.I = Rs. 3109