Answer:
that they are 200 mL of 70% and 100 mL of 40%
Step-by-step explanation:
We have to build a 2x2 system of equations with the information from the statement as follows:
0.70 * x + 0.4 * y = 300 * 0.6
x + y = 300 => x = 300 - y
where x is elixir 1 (70%) and y elixir 2 (40%).
replacing we have:
0.70 * (300 - y) + 0.4 * y = 300 * 0.6
210 * - 0.7 * y + 0.4 * y = 180
-0.3 * y = 180 - 210
y = -30 / -0.3
y = 100
now for x:
x = 300 - 100
x = 200
Which means that they are 200 mL of 70% and 100 mL of 40%