ANSWER
21 kg of the watermelon are water.
EXPLANATION
We have to divide the weight of the watermelon by 8 and then multiply by 7 - or in other words, multiply by 7/8:
[tex]24\times\frac{7}{8}=\frac{24}{8}\times7=3\times7=21[/tex]21 of the 24 kilograms of the watermelon are from water.
