Three dimes is equal to $.3 because 3 x .1 = <<3*.1=.3>>.3
Seven nickels is equal to $.35 because 7 x .05 = <<7*.05=.35>>.35
Each time he trades with dimes he lose $.05 because .3 - .25 = <<.3-.25=.05>>.05
Each time he traded with nickels he lost $.1 because .35 - .25 = <<.35-.25=.1>>.1
He lost $1 from trading with dimes because 20 x .05 =<<20*.05=1>>1
He lost $2 from trading with nickels because 20 x .1 = <<20*.1=2>>2
He lost $3 total because 1 + 2 = <<1+2=3>>3
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