Question

50 coins all dimes and quarters total is 10.25 how many dimes?

Answer 1

You can do these "in your head" like this:

50 dimes would be $5.00

Each quarter adds 15 cents.

10.25 - 55.00 = $5.25 added

Explanation:

525/15 = 35 quarters

--> 15 dimes

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or,

d + q = 50

10d + 25q = 1025

etc