Question 238262
volume of 20% salt solution = x


20% * x + 59% * 72 = 44% * (x + 72)
0.2x + 0.59 * 72 = 0.44 * (x + 72)
0.2x + 42.48 = 0.44x + 0.44 * 72
0.2x + 42.48 = 0.44x + 31.68
42.48 - 31.68 =0.44x - 0.2x
10.8 = 0.24x
x = 10.8/0.24 = 45


so, the volume of 20% salt solution to be added is 45 liters