Question

which machine is the least efficient? a screw driver with 89% efficiency a pulley with 85% efficiency a wheelbarrow with 79% efficiency

Explanation:

To determine the least efficient machine, we compare the efficiency percentages. The machine with the lowest percentage is the least efficient. The efficiencies are 89% (screwdriver), 95% (pulley), and 79% (wheelbarrow). 79% is the lowest.

Answer:

A wheelbarrow with 79% efficiency