Question

A 20% acid solution is mixed with a 70% acid solution to get 50 liters of a 40% solution.

Which of the following expressions is equal to 4(50)?

0.2x + 0.7y
2x + 7y
x + y

Answer 1

@seb.cal

Answer 2

@Callisto

Answer 3

x * 20 + y * 70 = 40 * 50
x + y = 50

20x + 70y = 2000
2x + 7y = 200

x = 50 - y

2 * (50 - y) + 7y = 200
100 - 2y + 7y = 200
5y =100
y = 20

x = 50 - y
x = 50 - 20
x = 30

30 liters of 20%
20 liters of 70%

Answer 4

so what is it?