Question

A scientist needs 60 liters of a 40% solution of alcohol. He has a 30% solution and a 60% solution available. How many liters of the 30% solution and how many liters of the 60% solution should he mix to make the 40% solution?

Answer 1

x = 40 liters of the 30% solution

y = 20 liters of the 60% solution

Explanation:

CREATE THE TABLE:

TYPE UNITS CONCENTRATION = AMOUNT

30% x 0.30 0.30x

60% y 0.60 0.60y

40% 60 0.40 0.40(60)

CREATE THE EQUATIONS:

x + y = 60

0.3x + 0.6y = 24

SOLVE:

x = 60 - y

0.3 (60 - y) + 0.6y = 24

y = 20 liters

x + 20 = 60

x = 40 liters