Aleza S. answered • 11/23/17

Tutor

New to Wyzant
Math and English enthusiast :)

Hi David!

You can solve this kind of problem with a system of linear equations.

x = kg of brand A

y = kg of brand B

We know the total weight of the mix is 50 kg, so:

x+y = 50

We know how much each kg costs and what the total cost is, so:

6x + 8y = 7.2(50)

If you don't have a graphing calculator, substitution is an easy way to solve this.

x+y = 50

y = 50 - x

6x +8y = 7.2(50)

6x +8(50-x)=360

6x-8x + 400 = 360

-2x = -40

x = 20

Since x + y = 50, we also know that y = 30.

Check your solution:

20(6) + 30(8) = 7.2(50)

360 = 360

Brand A: 20 kg

Brand B: 30 kg

Let me know if you have questions! :)