How much of each item must be mixed to get 7 cups of a mixture that is ​6.7% sodium​ hypochlorite?

Question

A bleach is

4.25​%

sodium hypochlorite and swimming pool shock treatment is

11.5​%

sodium hypochlorite. How much of each item must be mixed to get

7

cups of a mixture that is

6.7%

sodium​ hypochlorite?

Answer 1

You can use a procedure called alligation. Look it up if you don't get it.

HAVE............WANT..........CUPS......

4.25%..................................5..........

......................6.7%.....................

11.7%...............................2.45.......

So, you would need 5 cups of the 4.25% soln and 2.45 cups of the 11.7%, but that would produce 7.45 cups. So, to make 7 cups, we take 96% of these values to get

4.7 cups of 4.25%

2.3 cups of 11.7%