A chef is going to use a mixture of two brands of Italian dressing. (Math)

Question

A chef is going to use a mixture of two brands of Italian dressing. The first brand contains 6% vinegar, and the second brand contains 14% vinegar. The chef wants to make 320 milliliters of a dressing that is 7% vinegar. How much of each brand should she use?

Answer 1

x+y = 320

x = 320-y

6x+14y = 7(320)

(6)(320-y) + 14y =7(320)

8y = 7(320) -6(320) = 320

y = 320/8 = 40 ml of 14% vinegar

x = 320-40 = 280 ml of 7% vinegar

to get 320 ml of 14% vinegar

You might have guessed in the approximate range as 7% is much closer to 6% than it is to 14% so you know you'll need mostly 6% vinegar

7-6 = 1, 14-7=7

you'll need 7 times as much 6% vinegar. 280 = 4 times 40