Sanjeev invested \(\frac{1}{8}\) of a certain sum at 5% p.a. for two years and \(\frac{3}{5}\) of the sum at 6% p.a. for two years and the remaining at 10% p.a. for two years. If the total interest received is ₹1674, then the total sum invested is

₹12000

Let the sum invested = Rs. 4000

Interest on \(\frac{1}{8}\) of 4000 @5% for 2 years = 50 (500 × 5% × 2)

Interest on \(\frac{3}{5}\) of 4000 @6% for 2 years = 288 (2400 × 6% × 2)

Interest on remaining amount of 4000 # 10% for 2 years = 220 (1100 × 10% × 2)

Total interest = 50 + 288 + 220 = 558 → ×3 → 1674 (given)

so, sum invested = Rs. 4000 × 3 = Rs. 12000