how much 35% blend should he mix with the 20% blend to create a 12 oz cup of cafe au lait containing 30% steamed milk

Question

how much 35% blend should he mix with the 20% blend to create a 12 oz cup of cafe au lait containing 30% steamed milk

Answer 1

Let x = the amount of 35% blend and y = the amount of 20% blend. Then we have the following system of equations:

 

x + y = 12

 

.35x + .20y = .30(12)

 

I will multiply both sides of the second equation by 100 to clear decimals

 

35x + 20y = 360

 

We can use the Substitution Method to solve this system. If we solve the first equation for y, we get:

 

y = 12 - x

 

Now replace y in the second equation with (12 - x)

 

35x + 20(12 - x) = 360

 

You should now be able to solve this x and then determine y, Julia