P and Q have equal amounts. P invested half amount at 10% compound interest and remaining half at 6% simple interest for 2 years and Q invest half amount at 20% compound interest and remaining amount at 10% simple interest for 2 years. If the total interest received by both P and Q is Rs 15080, find the approximate sum.

Let the amount be x. P: half at 10% CI (2yr) gives 0.5x[(1.1)²-1] = 0.5x(0.21) = 0.105x. Half at 6% SI (2yr) gives 0.5x×0.06×2 = 0.06x. Total P = 0.165x. Q: half at 20% CI gives 0.5x[(1.2)²-1] = 0.5x(0.44) = 0.22x. Half at 10% SI gives 0.5x×0.10×2 = 0.10x. Total Q = 0.32x. Combined interest: 0.165x + 0.32x = 0.485x = 15080. x = 15080/0.485 ≈ 31093, rounds to 31000.