Question 995848: Mr. Cardenas has $8.70 in his pocket. it is all change but only quarters and dimes. there are a total of 48 coins. Answer by addingup(3677) (Show Source):
You can put this solution on YOUR website! q+d= 48 is the total of coins he has, so we can say that:
q= 48-d - - Substitute value
0.25q+0.10d= 8.70 Let's use the substitute value:
0.25(48-d)+0.10d= 8.7 Multiply on left
12-0.25d+0.10d= 8.7 Now add d on left and subtract 12 on both sides
-0.15d= -3.30 Now divide both sides by -15, and remember that - divided by -= +
d= 22 And:
q= 48-22= 26
Proof:
22*0.10= 2.20
26*0.25= 6.50
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Total.....8.70 we have the correct answer
