Question

Help? i do not understand how to get the answer...​

Answer 1

A

Explanation:

Let x ml be the amount of paint color B mixed with 40 ml of paint color A.

In 40 ml of paint color A are 15% of black pigment, so there are

`0.15\cdot 40\ ml`

of black pigment.

In x ml of paint color B are 60% of black pigment, so there are

`0.6\cdot x\ ml`

of black pigment.

In total we het x+40 ml of mixture. There are 25% of black pigment that is

`0.25\cdot (x+40)\ ml.`

Thus,

`0.15\cdot 40+0.6\cdot x=0.25\cdot (x+40).`