The simple interest on a certain sum for 8 years at 12% per annum is ₹ 3120 more than the simple interest on the same sum for 5 years at 14% per annum. Find the sum.
Sum = ₹ 12,000
SI₁ = (P × 12 × 8)/100 = 0.96P.
SI₂ = (P × 14 × 5)/100 = 0.7P.
Difference = 0.96P − 0.7P = 0.26P = 3120.
P = 3120 / 0.26 = ₹ 12,000.