Principal + Interest for 7 years = ₹ 7100
Principal + Interest for 4 years = ₹ 6200
∴ Interest for 3 years = ₹ 900
∴ Interest for 1 years = ₹ 300
Interest for 4 years interest = ₹ 300 × 4 = ₹ 1200
According to question
Principal + 4 years interest = ₹ 6200
or, Principal + ₹ 1200 = ₹ 6200
∴ Principal = ₹ 6200 – ₹ 1200 = ₹ 5000
Calculation of Rate
Rate = \frac{\text { Interest } × 100}{\text { Principal } × \text { Time }}
= \frac{1200 × 100}{5000 × 4} = 6
∴ Rate = 6 % and Principal = ₹ 5000