SOLUTION: how do I solve this problem by method of addition and substitution: A toll bridge costs $2. If you use the bridge x times in a month, the monthly cost , y is y=2x. With a $10 co

Algebra ->  Linear-equations -> SOLUTION: how do I solve this problem by method of addition and substitution: A toll bridge costs $2. If you use the bridge x times in a month, the monthly cost , y is y=2x. With a $10 co      Log On


   



Question 535696: how do I solve this problem by method of addition and substitution:
A toll bridge costs $2. If you use the bridge x times in a month, the monthly cost , y is y=2x. With a $10 coupon book the toll is redueced $1. The monthly cost, y, of using coupon book is y=x+10. How many times do use the bridge without the coupon book to to equal the cost with the coupon book.

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
You have the cost equations for both situations, so set these two equations equal to each other and solve for x.
y+=+2x and
y+=+x%2B10 Set these equal.
2x+=+x%2B10 Solve for x. Subtract x from both sides.
x+=+10
The monthly cost, y, will be the same if you use the bridge 10 times.
2%2810%29+=+10%2B10
20+=+20