Lenny is making his own laundry soap, the recipe calls for two parts of borax, two parts washing soda, and one part soap flakes. If Lenny uses 7 cups of soap flakes, how many cups of borax and washing soda combined does he need? Would it be 28 cups or 7 cups or 21 cups or 14 cups
The recipe calls for two parts of borax and two parts of washing soda for every one part of soap flakes. Since Lenny is using 7 cups of soap flakes, he would need 7 cups of borax and 7 cups of washing soda.
In total, Lenny would need 7 cups of borax + 7 cups of washing soda = 14 cups of borax and washing soda combined.
Therefore, the correct answer is 14 cups.