Explanation :
The efficiency of a machine is always less than 100 %. This is because some of the energy gets lost in the form of heat energy, sound energy and frictional energy.
Mathematically it is defined as :
[tex]\eta=\dfrac{W_o}{W_i}[/tex]
Where,
[tex]\eta[/tex] is the efficiency
[tex]W_o[/tex] is output work
[tex]W_i[/tex] is input work
Hence, this is the required explanation.
