A chef is going to use a mixture of two brands of Italian dressing. The first brand contains 8% vinegar, and the second brand contains 13% vinegar. The chef wants to make 270 milliliters of a dressing that is 9% vinegar. How much of each brand should she use

Amount of 8% vinegar = 216 mL

Amount of 13% vinegar = 54 mL

Step-by-step explanation:

First, of all, let x be the amount of 8% vinegar used

Since, the scientist needs 270 mL of vinegar, then;

Let 270 - x be the amount of 13% vinegar used

Now, we are told that she needs 270 mL of a 9% vinegar.

This means that;

8%x + 13%(270 - x) = 9%(270)

Simplifying this gives;

0.08x + 0.13(270 - x) = 0.09 × 270

Expanding the bracket gives;

0.08x + 35.1 - 0.13x = 24.3

0.13x - 0.08x = 35.1 - 24.3

0.05x = 10.8

x = 10.8/0.05

x = 216 mL

Thus, she will need to use 216 mL of the 8% vinegar.

Since 270 - x is the amount of 13% vinegar used , then;

the amount of 13% vinegar = 270 - 216 = 54 mL