Radhika borrowed ₹ 12000 from her friends. Out of which ₹ 4000 were borrowed at 18% and the remaining at 15% rate of interest per annum. What is the total interest after 3 years?

Total amount borrowed by Radhika = ₹12,000

The amount borrowed by her at 18% p.a. = ₹4,000

∴ Interest = (P × R × T) / 100 = (4,000 × 18 × 3) / 100 = ₹2,160

Remaining amount = ₹12,000 − ₹4,000 = ₹8,000

Interest on ₹8,000 = (P × R × T) / 100 = (8,000 × 15 × 3) / 100 = ₹3,600

Total interest = ₹2,160 + ₹3,600 = ₹5,760

Hence, the total interest = ₹5,760.