The rate of simple interest on a sum of money is 5% p.a. for the first 4 years, 8% p.a. for the next 3 years and 10% p.a. for the period beyond 7 years. If the simple interest accrued by the sum over a period of 10 years is ₹1,850, then the sum is:

Simple interest = $$\frac{prt}{100}$$

p = principal

r = rate of interest

t = time
Simple interest for 10 years = 1,850

Simple interest for 4 years at 5% + Simple interest for 3 years at 8% + Simple interest for 3 years at 10% = 1850

$$\frac{p \times 5 \times 4}{100} + \frac{p \times 8 \times 3}{100} + \frac{p \times 10 \times 3}{100}$$ = 1850

$$p(20 + 24 + 30) = 185000$$
p = 185000/74 = 2500

$$\therefore$$ The sum is Rs.2500.