Answer:
20 liters of 50% solution and 80 liters of 25% solution
Explanation:
Let x litres be the amount of 50% solution to be used.
Since the amount of 25% solution used is 20 liters less than 5 times the amount of 50% solution used, then the 25% solution would be (5x -20) litres.
Therefore, 50x + 25(5x-20) = 30(x + 5x-20)
50x + 125x - 500 = 30x + 150x - 6 00
175x - 500 = 180x - 600
Collecting like terms
180x - 175x = 600 - 500
5x = 100
x = 20
Therefore, volume of 50% solution needed = 20 litres
Volume of 25% solution needed = (5 * 20) - 20 = 80 litres
20 liters of 50% solution and 80 liters of 25% solution