Question 721508
Start with these equations:
Let x=the #of quarters Let y=the number of dimes.
X+Y=40
.10X+.25Y=8.50
(The values are .10 and .25 because a dime is equivalent to .10 of a dollar and a quarter is .25 of a dollar)
Now, solve by substitution!
X+Y=40--->Y=40-X
Then, substitute the Y value into the other equation.
.10X+.25(40-X)=8.50
.10X+10-.25X=8.50
Combine Like Terms
10-0.15X=8.50
Bring the 10 over to the other side.
-0.15X=-2.50
Divide both sides by -0.15
Find your answer from there. I led you most of the way, now it is your turn to think. Good luck! If you still need help, email me. :)