A block and tackle pulley system of 6 pulley uses 300N to overcome 1200N. find efficiency

66.7%

Explanation:

There are 6 pulleys, so the mechanical advantage is 6.

The theoretical force needed to overcome 1200 N is therefore:

1200 N / 6 = 200 N

The actual force is 300 N. So the efficiency is:

200 N / 300 N * 100% = 66.7%