The three friends had meals worth 10 * 3 = <<10*3=30>>30 dollars
If they paid for the meals only, they would have remained with 45 - 30 = <<45-30=15>>15 dollars.
Dividing the remaining amount by the number of ice cream scoops gives 15/3 = <<15/3=5>>5 dollars.
Each scoop of ice cream cost 5 dollars
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