Answer:
Amodeo needs 20 litres of the 20% solution and 40 litres of the 50% solution to make 60 litres of 40% solution.
Explanation:
this can be solved as system of equations:
0.2x + 0.5y = 0.40(60)
x + y = 60
0.2x + 0.5y = 24
x + y = 60
move the y
x = 60 - y
0.2(60 - y) + 0.5y = 24
12 - 0.2y + 0.5y = 24
12 + 0.3y = 24
0.3y = 12
y = 40
plug in new value for y
x = 60 - 40
x = 20