SOLUTION: a boy has 14 coins in his pocket, dimes and quarters. he has $2.75 how many dimes and quarters? how do i solve this? i have two equations, (.10)*d+(.25)*q=2.75 and d+q=14 wha

Algebra ->  Customizable Word Problem Solvers  -> Coins -> SOLUTION: a boy has 14 coins in his pocket, dimes and quarters. he has $2.75 how many dimes and quarters? how do i solve this? i have two equations, (.10)*d+(.25)*q=2.75 and d+q=14 wha      Log On

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Question 338253: a boy has 14 coins in his pocket, dimes and quarters. he has $2.75 how many dimes and quarters?
how do i solve this? i have two equations, (.10)*d+(.25)*q=2.75 and d+q=14
what now?

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
substitution

d = 14 - q

multiplying by 100 to clear decimals ___ 10d + 25q = 275

substituting for d ___ 10(14 - q) + 25q = 275 ___ 140 - 10q + 25q = 275

15q = 135 ___ q = 9

d = 14 - (9) = 5