SOLUTION: Parker has quarters and dimes in his piggy bank. He has 4 more dimes than quarters, and he has a total of $7.05 in his bank. How many dimes and quarters does Parker have? I hav

Question 969906: Parker has quarters and dimes in his piggy bank. He has 4 more dimes than quarters, and he has a total of $7.05 in his bank. How many dimes and quarters does Parker have?
I have tried to help my son with this problem, but I am not sure how to figure this one out.
Found 2 solutions by macston, josgarithmetic:
Answer by macston(5194) (Show Source): You can put this solution on YOUR website!
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Q=quarters; D=dimes=Q+4
.
$0.25Q+$0.10D=$7.05 Substitute for D from given.
$0.25Q+$0.10(Q+4)=$7.05
$0.25Q+$0.10Q+$0.40=$7.05 Subtract $0.40 from each side.
$0.35Q=$6.65 Divide each side by $0.35
Q=19
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ANSWER 1: There are 19 quarters.
.
D=Q+4=19+4=23
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ANSWER 2: There are 23 dimes.
.
CHECK:
$0.25Q+$0.10D=$7.05
$0.25(19)+$0.10(23)=$7.05
$4.75+$2.30=$7.05
$7.05=$7.05

Answer by josgarithmetic(39626) (Show Source): You can put this solution on YOUR website!
Assign variables to the count of each coin:
q, quarters
d, dimes

Make equations from the description:

;
The first equation is for the description between dimes and quarters. The second equation is accounting for amount of money. Notice one-tenth a dollar per one dime, and quarter of a dollar per "quarter".

The money count equation should be simplified before continuing to process the system.
, if you know those common fraction equivalents.
LCD is 20, hopefully understood from earlier learned skills and knowledge;
---multiply left and right members by 20.

Revise the system of equations:

Your son should know what to do from that. Choice of method either is substitution, or Elimination. Elimination may be easiest at least part-way, if he knows it yet.
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