Question

A scientist has 400ml of a 8% solution. How much water needs to be added to lower it to a 2% solution?

Answer 1

1,200 ml of water must be added

Explanation:

Let

x ----> the amount of water needed in ml

we know that

In a 8% solution, the amount of water is 92%

so

`400(0.92)=368\ ml`

In a 2% solution the amount of water must be 98%

so

`(400+x)0.98=368+x`

solve for x

`392+0.98x=368+x\\x-0.98x=392-368\\0.02x=24\\x=1,200\ ml`