Can a machine be more than 100% efficient?

yes

no

impossible to determine

No, simple machine will have an efficiency of 100% if he output work of the machine is equal to the work input.

Impossible to determine

Explanation:

In other words, no machine can be more than 100% efficient. Machines cannot multiply energy or work input ... If a machine were 100% efficient then it can't have any energy losses to friction, so no friction can be present. In that case the theoretical and actual mechanical advantages would be equal.