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Wanda has $3.55 in dimes and quarters. She has 3 more quarters than dimes. How many quarters does she have?

0.10d + 0.25q = 3.55

q = d + 3

0.10d + 0.25 (d + 3) = 3.55

0.10d + 0.25d + 0.75 = 3.55

0.10d + 0.25d = 3.55 - 0.75

0.35d = 2.80

d = 2.80/0.35

d = 8 ... 8 dimes

q = d + 3

q = 8 + 3

q = 11 < = = = 11 quarters