An effort of 5 units is applied on a 10-unit load. The distance travelled by the effort and the load are 50 and 20 units, respectively. Find the efficiency of this machine.

Correct option is D

Given: Effort = 5 units
Load = 10 units
Mechanical advantage = Load  / Effort  =10/5=2unit
and velocity ratio = Distance travelled by effort  / Distance travelled by load 
=50/20
From formula Mechanical advantage = Velocity ratio × Efficiency