The restaurant purchased a new washing machine which uses less water and energy. The new washing machine uses 2 tablespoons of detergent per load while the old mushing machine used 1/4 cup per load if the restaurant washes 42 loads in one month, how many tablespoons will be saved monthly.

First, we need to convert the measurements to a common unit.

1/4 cup is equivalent to 4 tablespoons.

So the old washing machine used 4 tablespoons of detergent per load.

The new washing machine uses 2 tablespoons of detergent per load.

The difference in detergent used per load is 4 - 2 = 2 tablespoons.

If the restaurant washes 42 loads in one month, the total amount of detergent saved monthly is 2 tablespoons/load * 42 loads = 84 tablespoons.

Therefore, the restaurant will save 84 tablespoons of detergent monthly by using the new washing machine.