Answer: 4 hours
Explanation:
Assume x is the number of hours taken.
Garage A would therefore charge a total of:
= $9 + $1.50 * x
= 9 + 1.50x
Garage B would charge:
= $5 + $2.50 * x
= 5 + 2.50x
To find the number of hours it would take for them to be the same, equate both equations:
9 + 1.50x = 5 + 2.50x
9 - 5 = 2.50x - 1.50x
4 = 1x
x = 4 hours
That cost would be:
= 9 + 1.50 * 4
= 9 + 6
= $15