The actual mechanical advantage of a pulley is 2. The pulley has 3 supporting strings. What is the efficiency of the pulley?

50%

66%

100%

150%

Efficiency is the ability to avoid wasting energy, materials, money, time, and effort in producing a desired result. We know the formula to find the answer AMA/IMAx100. Three supporting strings should have given M. A. of 3 provided that this is without friction. Since there are only 2, the efficiency is 2/3 = 66%.