Question 1059580
q = d+6 since she has 6 quarters more than dimes, if you want to make them equal you have to add 6 to the dimes or subtract 6 from the quarters.
Each quarter is 25 cents, or 0.25 of a dollar (a dollar has 100 cents), we'll call them 0.25q
Each dime is 10 cents, we'll call them 0.10d
:
0.25q+0.10d = 6.40 Above I said that q = d+6. Substitute in this equation:
0.25(d+6)+0.10d = 6.40 distribute the 0.25, like this:
0.25d+1.50+0.10d = 6.40 Add d on left and subtract 1.50 on both sides:
0.35d = 4.90 divide both sides by 0.35
d = 14 She has 14 dimes and 14+6 = 20 quarters.
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Check:
14*0.10 = 1.40
20*0.25 = 5
Total . . 6.40 Correct