SOLUTION: There are 36 coins in a bag, all are quarters and dimes. There are half as many dimes as quarters and the value of the coins in the bag totals $7.20. How many dimes(D) are in th

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Question 970162: There are 36 coins in a bag, all are quarters and dimes. There are half as many dimes as quarters and the value of the coins in the bag totals $7.20.
How many dimes(D) are in the bag?
How many quarters(Q) are in the bag?
Answer by josgarithmetic(39623) About Me  (Show Source):
You can put this solution on YOUR website!
q, d, quarters and dimes

system%28q%2Bd=36%2Cd%2Fq=1%2F2%2C0.1d%2B0.25q=7.2%29
and the description and system are overstated. Any TWO of the equations should be enough for the problem and the next equation needs to be in agreement with the solution found.


Using only the first two equations as a system:

system%28q%2Bd=36%2Cd=q%2F2%29

q%2Bq%2F2=36

2q%2Bq=72

3q=72


highlight%28q=24%29-----------meaning that must have highlight%28d=12%29.

That solution MUST satisfy the money count equation.
0.1d%2B0.25q=7.2
%280.1%29%2812%29%2B%280.25%2924=7.2
1.2%2B6.0=7.2
7.2=7.2
Ths solution worked.