Question
A payment of ₹120 is made with ₹10, ₹5 and ₹2
coins. A total of 25 coins are used. Which of the following is the number of ₹10 coins used in the payment?Solution
Total coins used = 25. let the number of ₹10 coins = x Number of ₹5 coins = y Number of ₹2 coins = z Total number of coins = x + y + z = 25 ........(1) Total money = 10x + 5y + 2z = 120 ..........(2) from equation (1), we get z = 25 - x - y put this value in equation (2), we get 8x + 3y = 70 so, if x = 8, then y = 2 then, z = 25 - 8 - 2 = 15 required answer = 8
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