Answer:
2.25 hours
Step-by-step explanation:
Let for x hours the total charges in school A and B are same,
For school A,
Fixed charges = $ 7,
Additional charges per hour = 20
Thus, the total charges for x hours = 7 + 20x
For school B,
Fixed charges = $ 25,
Additional charges per hour = $ 12,
Thus, the total charges for x hours = 25 + 12x
[tex]\implies 7 + 20x = 25 + 12x[/tex]
[tex]20x - 12x = 25 - 7[/tex]
[tex]8x = 18[/tex]
[tex]\implies x = \frac{18}{8}=2.25\text{ hours}[/tex]