Question 857852
She would have needed 2.70 more if she used dimes.
2.70 divided by the difference between a quarter and a dime (.15) = 18
18 quarters is $4.50
If she had used 18 dimes, the total would have been $1.80.  Add that to the 27 more coins ($2.70) to get $4.50.
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Interesting word problem!