Question

A 25% acid solution must be added to a 40% solution to get 240 liters of 30% acid solution. How many of each should be used ?

Answer 1

Answer:

The number of liters of 25% acid solution = x = 160 liters

The number of liters of 40% acid solution = y = 80 liters

Step-by-step explanation:

Let us represent:

The number of liters of 25% acid solution = x

The number of liters of 40% acid solution = y

Our system of Equations =

x + y = 240 liters....... Equation 1

x = 240 - y

A 25% acid solution must be added to a 40% solution to get 240 liters of 30% acid solution.

25% × x + 40% × y = 240 liters × 30%

0.25x+ 0.4y = 72...... Equation 2

We substitute 240 - y for x in Equation 2

0.25(240 - y)+ 0.4y = 72

60 - 0.25y + 0.4y = 72

Collect like terms

- 0.25y + 0.4y = 72 - 60

0.15y = 12

y = 12/0.15

y = 80 Liters

Solving for x

x = 240 - y

x = 240 liters - 80 Liters

x = 160 liters

Therefore,

The number of liters of 25% acid solution = x = 160 liters

The number of liters of 40% acid solution = y = 80 liters