Hridaya opened her piggy bank and found coins of denominations Rs. 1, Rs. 2, Rs. 5 and Rs. 10 in the ratio 10 : 5 : 2 : 1. If there are 72 coins in all, then how much money (in Rs.) was there in the piggy bank in the form of coins?

Ratio is 10:5:2:1, so total parts = 18. Each part = 72/18 = 4 coins. Rs. 1: 40 coins, Rs. 2: 20 coins, Rs. 5: 8 coins, Rs. 10: 4 coins. Total = 40×1 + 20×2 + 8×5 + 4×10 = 40 + 40 + 40 + 40 = Rs. 160. The pattern is that each denomination contributes the same amount (Rs. 40) to the total because the ratio is weighted inversely to denomination value.