SOLUTION: jenny has 40 coins in her purse, comprised completley of dimes and quarters. if the total value of the coins is $8.05, how many dimes are in the coin purse?

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Question 1036880: jenny has 40 coins in her purse, comprised completley of dimes and quarters. if the total value of the coins is $8.05, how many dimes are in the coin purse?
Found 2 solutions by ikleyn, jorel555:
Answer by ikleyn(52800)   (Show Source): You can put this solution on YOUR website!
.
jenny has 40 coins in her purse, comprised completely of dimes and quarters. if the total value of the coins is $8.05,
how many dimes are in the coin purse?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 

Let d = the number of dimes.
Then the number of quarters is (40-d).

The dimes contribute 10d cents to the total.
The quarters contribute 25*(40-d) cents.

The total is 10d + 25(40-d) cents, and it is equal to 805 cents.

It gives you an equation

10d + 25(40-d) = 805.

Simplify and solve:

10d + 1000 - 25d = 805.

-15d = 805 - 1000,

-15d = -195,

d =  = 13.

There are 13 dimes and 40-13 = 27 quarters.

Answer.  13 dimes and 27 quarters.

Check.   13*10 + 25*27 = 805.  OK!


Answer by jorel555(1290)   (Show Source): You can put this solution on YOUR website!
Let d be the number of dimes; then quarters are 40-d. So:
10d+25(40-d)=805
10d+1000-25d=805
15d=195
d=195/15=13 dimes;
40-13=27 quarters!!!!!!!!!!!!!
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