Answer:
3 hours
Explanation:
The equation will be
10b+25t ≤ 130 (b = hours of babysitting, t = hours of tutoring)
Plug in the 4 hours of tutoring
10b+(25 times 4) ≤ 130
= 10b+100 ≤ 130
10 times 3 = 30, which answers the question
Since 100 + 30 = 130
Therefore, the answer to the minimum amount of hours Robert has to tutor
to make a minimum of $130 is . . .
3