let 'x' represent the water needed for 2/4 of a load

2 1/7 = (2*7 + 1)/7 = 15/7

(15/7) : 1 = x : (2/4)

by solving we find:

x = 15/14

x = 1 1/14

click here to see the step by step solution of the equation:

1 1/14 of water is needed for 2/4 of a load.