Question

a chef needs 6 L of a solution that is 70% of sugar. he has a 30% sugar mixture and an 80% sugar mixture that he can combine to the 70% mixture. let X represent the number of the liters of the 30% sugar mixture and let Y represent the number of liters of the 80% sugar mixture. how many liters of 30% sugar mixture is there?

Answer 1

1.2 litres of the 30% solution.

Explanation:

0.30x + 0.80y = 0.70(x + y)

0.30x - 0.70x + 0.80y - 0.70y = 0

-0.40x + 0.10y = 0

Also

x + y = 6

Multiply the third equation by 10:

-4x + y = 0

Subtracting the last 2 equations:

5x = 6

x = 6/5 = 1.2 litres.