Question

Allison needs 18 liters of 5% saline solution . She has a 1% solution available. How many liters of the 1% solution and how many liters of the 10%solution should she mid to make the 5% solution

Answer 1

10 litres of 1% solution and 8 litres of 10% solution

Explanation:

Let vol of 1% solution = x

So vol of 10% solution = 18 - x

5% of 18 litres = 0.9

Equation formed is

x * (1/100) + (18 - x)*(10/100) = 0.9

x + (18 - x)10 = 0.9 * 100

x + 180 - 10x = 90

-9x = 90 - 180

-9x = -90

x = 10 litres

10 litres of 1% solution and 8 litres of 10%