10(x+1) + 5x = 100 = $1

15x = 90

x = 6 ie., (10c × 7) + (5c × 6) = 70c + 30c = $1.

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If you are given change for $1 in 5c and 10c pieces, and you get 1 more 10c than 5c, how many of each are there?

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