SOLUTION: A collection of nickels, dimes, and quarters amounts to $7.50. If there are 120 coins in all and there are twice as many dimes as there are quarters, find the number of nickels.

Algebra ->  Customizable Word Problem Solvers  -> Coins -> SOLUTION: A collection of nickels, dimes, and quarters amounts to $7.50. If there are 120 coins in all and there are twice as many dimes as there are quarters, find the number of nickels.       Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 915196: A collection of nickels, dimes, and quarters amounts to $7.50. If there are 120 coins in all and there are twice as many dimes as there are quarters, find the number of nickels.
Answer by josgarithmetic(39623) About Me  (Show Source):
You can put this solution on YOUR website!
0.05%2An%2B0.10d%2B0.25q=7.50
highlight_green%28n%2B2d%2B5q=150%29

highlight_green%28n%2Bd%2Bq=120%29

2%2F1=d%2Fq
highlight_green%282q=d%29
The simple way to do is substitute for d in the other two equations, and simplify; and then solve the system of the TWO linear equations in n and q.