How do i get 217.14 divided by 21?

What is the unit rate of, 75% high fiber chimp food to 25% high protein chimp food.

How many liters of peroxide should be added to 12 liters of an 8% peroxide solution so that the resulting solution contains 16% peroxide?   original added new amount of peroxide 0.96 liters x 0.96 + x amount of solution 12 liters x 12 + x 0.18 liter 1.14 liters 1.92 liters 2.10 liters

Explain how the quotient of powers was used to simplify this expression.