Answer:
29 minutes
Step-by-step explanation:
You can set this up in a linear equation in slope-intercept form, where the y-intercept is the entry fee, y is the total cost, and the slope is the charge per minute. x will be the number of minutes he spent on the trampoline:
y=mx+b
43.25=1.25x+7
Then simplify:
36.25=1.25x
x=29
Therefore, he spent 29 minutes on the trampoline.