Question

A 100-pound watermelon is out in the sun. 99% of the watermelon's weight is water. After a few hours, 98% of the watermelon's weight is water. How many pounds of water have evaporated?

Answer 1

100 lbs = 1 lb of melon 99 lb water

Let "x" be weight of water:

percentage = weight of water / (1 lb melon + water)  
.98 = x / (1 lb melon + x)
.98 = x / 1 +x
.98 + .98x = x
.98 = .02x
x = 49

49 lbs of water
1 lb melon + 49 lbs water = 50 lbs total

49 / 50 = 98%
Therefore, 50 POUNDS of water evaporated