If ₹64 amounts to ₹83.20 in 2 years on simple interest, then how much will ₹86 amount to in 4 years at the same rate percent per annum?
Answer & explanation
Correct answer: option 4
Principal P1 = 64
Time T1 = 2 years
Amount A1 = 83.20
Simple interest S1 = A1 - P1 = 83.2-64 = 19.2
Assume Rate per annum, R1
19.2 = 64*2*R1/100
R1 = 1920/128
If P2 = 86
T2 = 4 years
and R2 = R1
Then, S2= 86*4*1920/(128*100) = 86*60/100 = 51.6
A2 = P2+S2 = 51.6+86 = 137.60
The correct answer is Option (4) → ₹137.60