A box half full of apples weighs 40kg and the same box one fifth full weighs 22kg, what does the box weigh when empty?

1/2 = 40kg

1/5 = 22kg

1/2 = 5/10

1/5 = 2/10

3/10 is the difference between 18kg.

This means 1/10 of the box filled with apples is 6kg.

40 - (5 x 6) = 10kg. The box weighs 10kg alone.

1/2 = 40kg

1/5 = 22kg

1/2 = 5/10

1/5 = 2/10

3/10 is the difference between 18kg.

This means 1/10 of the box filled with apples is 6kg.

40 - (5 x 6) = 10kg. The box weighs 10kg alone.