Question

A recipe calls for 5 cups of flour for every 6 teaspoons of salt. If you wanted to make a larger batch of the same recipe with 15 cups of flour, how much salt would you need?

Answer 1

Because you times 5 by 3 to get 15, you times 6 by 3, which is 18. So 18 tsp of salt for this recipe.

Answer 2

The problem can be solved by proportion as following

5 cups of flour for every 6 teaspoons of salt
15 cups of flour for every x teaspoons of salt


∴ 5 : 6 = 15 : x
∴
`(5)/(6) = (15)/(x)`
By using cross multiplication
∴ 5 x = 6 * 15
∴ 5 x = 90

∴ x = 90/5 = 18


So, the amount of salt needed = 18 teaspoons of salt