<PRE><B>Question 264611</B>
.30X+.20(52-X)=12.80
.30X+10.4-.20X=12.80
.10X=12.80-10.4
.10X=2.40
X=2.40/.10
X=24 CARDS COST $.30.
52-24=28 CARDS COST $.20.
PROOF:
.30*24+.20*28=12.80
7.2+5.6=12.80
12.80=12.80
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