Apulley with a mechanical advantage of 5 will require you to pull times the amount of rope.

a. 1/5
b. 5
c. 10
d. 15

It will require a force of 1/5, answer A.

Explanation:

In the attached image we can see an example of an array of pulleys that will lift a 100 kg-f load.

If we analyze pulleys A,B, and C as in the image we can check a force in the cable of 20kg-f.

In the pulley D we have three forces of 20 kg-f each and those forces plus the forces in the pulley B, sum a total of 100 kg-f (60+40). This matches the mechanical advantage (100/5) = 20 kg-f

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