A chef is going to use a mixture two different brands of Italian dressing the first spring and days 5% vinegar the second brain contains 15% vinegar the sheriff wants to make 390$ ml addressing that is 9% vinegar how much of each brand should she use

I guess the chef is making the mixture for the sheriff... Let x be the amount of dressing with 5% vinegar that is required, and y the amount of 15% vinegar dressing (both amounts in mL).

The sheriff wants 390 mL of the mixed dressing, so that

x + y = 390

x mL of the 5% dressing contains 0.05x mL of vinegar, while y mL of the 15% dressing contains 0.15y mL of vinegar. The resulting mixture should have a concentration of 9% vinegar, so that it contains 0.09 (390 mL) = 35.1 mL of vinegar. This means

0.05x + 0.15y = 35.1

Solve for x and y :

y = 390 - x

0.05x + 0.15 (390 - x) = 35.1

0.05x + 58.5 - 0.15x = 35.1

23.4 = 0.10x

x = 234

y = 156

.25

step-by-step explanation: