The recipe calls for 2 parts borax and 2 parts washing soda. Therefore, the total number of parts for borax and washing soda is 2 + 2 = 4 parts.
Since Lenny is using 7 cups of soap flakes, which is 1 part, we can find the number of parts for borax and washing soda by dividing 7 by 1: 7 / 1 = <<7/1=7>>7 parts.
To find the number of parts for borax and washing soda, we divide 7 parts by 4: 7 / 4 = <<7/4=1.75>>1.75 parts.
Since 1 part is equal to 7 cups, Lenny needs to use 1.75 * 7 = <<1.75*7=12.25>>12.25 cups of borax and washing soda combined. Answer: \boxed{12.25}.
Lenny is making his own laundry soap. The recipe calls for 2 parts borax, 2 parts washing soda, and 1 part soap flakes. If Lenny uses 7 cups of soap flakes, how many cups of borax and washing soda combined does he need
1 answer