Final answer:
If Lenny uses 7 cups of soap flakes, he will need 14 cups of borax and 14 cups of washing soda, making 28 cups combined according to the two-to-one ratio of the recipe.
Step-by-step explanation:
Lenny's recipe for homemade laundry soap is based on a ratio of two parts borax, two parts washing soda, and one part soap flakes. If Lenny uses 7 cups of soap flakes, then he needs equal parts of borax and washing soda to match the recipe's two-to-one ratio.
Since Lenny uses 7 cups of soap flakes (one part), he would need 14 cups of borax and 14 cups of washing soda, making a total of 28 cups combined. This is because the recipe calls for two parts of each of these ingredients for every one part of soap flakes.
Step-by-Step Explanation:
Identify the ratio in the recipe: two parts borax: two parts washing soda: one part soap flakes.
Since 1 part equals 7 cups of soap flakes, then 2 parts equal 7 cups x 2 = 14 cups.
Calculate the amount of borax needed: 14 cups (as it is two parts according to the recipe).
Calculate the amount of washing soda needed: 14 cups (as it is two parts according to the recipe).
Add the amounts of borax and washing soda together: 14 cups + 14 cups = 28 cups.