The ideal mechanical advantage (i.e. the ratio of the weight W to pull P for equilibrium) of the combination of pulley shown is

Concept:

Mechanical Advantage: In a simple machine when the effort (P) balances a load (W), the ratio of the load to the effort is called M.A.

\(M.A. = \frac{{Load}}{{Effort}} = \frac{W}{P}\)

Calculation:

Given:

From the given figure, we can come up to above force diagram.

Assumptions:

• The string is massless and inextensible.
• The pulley is massless and smooth.

For the pulley mass system in equilibrium,

W = 4P

\(\frac{W}{P}~=~4\)

Hence the ideal mechanical advantage of the combination of pulley shown is 4.

Note:

• The question cannot be solved by the given figure.
• Since it is same given in the official paper, we can redraw it as the above diagram.
• The official answer they provided was also based on the above diagram only.