Answer:
106
Step-by-step explanation:
The diameter of the wheel is 15 cm or 0.15 m.
The circumference of the wheel is 0.15π m ≈ 0.47 m.
So the wheel moves 0.47 m with each revolution.
The wheel travels 50 m, so the number of revolutions is:
(50 m) / (0.47 m/rev) ≈ 106 revolutions.
Answer: 18/80=0.225
81 hours
Let x be the time are needed
45:5 = x:9
5x = 45×9
5x = 405
x = 81