Question

James has $10 in 5-cent and 10-cent coins in his change jar and counts 157 coins in total. How many 10-cent coins does he have?

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Answer 1

10 cent coins = 43

Explanation:

x = 10 cent coins

y = 5 cent coins

x + y = 157, then y = 157 - x

$10 = 1000 cents

0.10x + 0.05y =1000

substitute for y:

0.10x + 0.05(157 - x) = 1000

0.10x + 7.85 - 0.05x = 1000

combine like terms:

0.05x = 2.15

x = 43

y = 114