linear equations with two unknown

Question

Silvia wants to mix a 40% apple juice drink with pure apple juice to make 2 L of a juice drink that
is 80% apple juice. How many Liters of each should she use? (Hint: Pure apple juice is 100%
apple juice.)  state solution in ordered pair

Answer 1

Let F = amt of 40% juice and P = amt of 100% juice

Sylvia wants to make 2 L, i.e. F + P = 2

 

In the resulting mixture there will be .8 * 2 liters of pure juice and it will be made from .4F liters of 40% juice and P liters of pure juice, i.e. .4F + P = 1.6

 

F + P = 2

.4F + P = 1.6

 

Subtract: .6F = .4

F = 2/3 and P = 1 1/3

 

Check: (2/3) * 2/5 + 4/3 = (4/15) + (20/15) = 24/15 = 8/5 = 1.6