Question

a recipe calls for 10 tablespoons of milk for every 21 cups of flour. If the chef puts in 168 cups of flour how many tablespoons of milk does the chef have to put in

Answer 1

x = tablespoons of milk

Proportion:

21 cups of flour / 10 tablespoons of milk = 168 cups of flour / x tablespoons of milk

21 / 10 = 168 / x

Cross multiply

21 ∙ x = 10 ∙ 168

21 x = 1680

Divide both sides by 21

x = 1680 / 21 = 21 ∙ 80 / 21 = 80

80 tablespoons of milk