Question

the simple interest on a certain sum for three one and half years at 7% per P. A is rupees 225 more than the simple interest on the same sum for 4 years at 5%. Find the sum

Answer 1

Case I:
Rate of interest = 7%
Time = 3 1/2 years = 7/2 years
Let the Principal = P
Simple interest = (P × T × R) / 100
SI = (P × 7/2 × 7) / 100

Case II:
Rate of interest = 5%
Time = 4 years
Let the Principal = P
Simple interest = (P × T × R) / 100
SI = (P × 4 × 5) / 100

Difference between the interests = Rs 225
⇒ [(P × 7/2 × 7) / 100] - [(P × 4 × 5) / 100] = 225
⇒ 0.245 P - 0.2 P = 225
⇒ 0.045 P = 225
⇒  P = 5000
Therefore, the sum of money is RS 5000.