The weight of the box with grapes is 9kg, when half of the grapes were sold, the weight of the box

The weight of the box with grapes is 9kg, when half of the grapes were sold, the weight of the box with the remaining grapes was 5kg. How many kg of grapes were in the box?

1. Suppose that the mass of grapes in the box is x kg.

2. Since the grapes together with the box have a mass equal to 9 kg, therefore the box itself weighs (9 – x) kg.

3. Half of the grapes in the box will have a mass equal to (x / 2) = x / 2 kg.

3. Let’s make an equation and find out how many kg of grapes were in the box, if we know that the mass of half of the grapes together with the box is 5 kg.

x / 2 + (9 – x) = 5;

x / 2 + 9 – x = 5;

9 – 5 = x – x / 2;

18 – 10 = 2x – x;

x = 8 kg.

Answer: The mass of grapes in a box is 8 kg.