The difference in compound interest, and simple interest on a certain amount at 10% per annum at the end of the third year is RS. 620. What is the principal amount?
A
40000
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
12000
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
10000
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
20000
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution
The correct option is D 20000 Let the sum be Rs.x. Then,CI=x(1+10100)3−x=(13311000x−x)=331x1000S.I.=x×10×3100=3x10∴(C.I)−(S.I)=(331x1000−3x10)=31x1000∴31x1000=620orx=20000.Hence, the principal amount is Rs. 20000.Alternative:(CI−SI)3Y=3P(R100)2+P(R100)3.