SOLUTION: John has a total of 13 coins in his pocket. Of the 13 coins, they are all either quarters or dimes. The total value of the coins is $2.50. How many dimes does John have in his pock

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Question 237327: John has a total of 13 coins in his pocket. Of the 13 coins, they are all either quarters or dimes. The total value of the coins is $2.50. How many dimes does John have in his pocket?
Answer by solver91311(24713) About Me  (Show Source):
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Let represent the number of dimes

Let represent the number of quarters

Then represents the value of the dimes in cents

And represents the value of the quarters in cents

Finally, the total value, $2.50, is 250 expressed in cents

So:



and



Solve the system by substitution. Solve the first equation for q in terms of d. Substitute the expression for q into the second equation giving you an equation in d. Solve for d to get your answer.


John