Matt has 20 coins in his back pack, all dimes and quarters. The value of a dime is $0.10 and the value of a quarter is $0.25. If the value of the coins is $3.95, how many coins does he have?

Question

It asks to fill in:

1. variables
2. equation
3. solutions

I know that a possible equation could be 0.10d + 0.25q = 3.95 but how do I go from there?

Thanks!!

Answer 1

Good start!

You'll just want to add a second constraint, based on what we know, and that would be that the # of dimes and quarters = coin total of 20 or (using your variables):

d + q = 20

Then, you can solve by substituting 20 - d for q into your original equation to obtain the solution for d, and plug solution for d back into the d + q = 20 equation to obtain q, make sense?

Hope this helps,

Todd