A giant watermelon weighed 100 pounds and was 99% water by weight in pounds. While standing in the sun, some water evaporated, so that the watermelon was only 98% water by weight in pounds. How many pounds did the watermelon then weigh?

Question

anonymous · Answer

hmm

foolaroundmath · Answer

Initially:
Weight of non-water substance = 1 pound (1% of 100 pounds)
Weight of water = 99 pounds

Suppose 'x' pounds of water evaporated.
Now, weight of water = 99 -x pounds
Weight of non-water substance remains same as before = 1 pound
Percentage of water now = weight of water/total weight
= (99-x)*100/(99-x+1)

This is given to be 98

Thus, 
$$\frac{99-x}{100-x} = \frac{98}{100}$$
see if you can solve this

anonymous · Answer

9900 - 100x = 9800 - 98x
100 = 2x
x = 50?

foolaroundmath · Answer

yes .. x is the weight of water evaporated, new weight = 99-x +1 = 100-x = 50 pounds

anonymous · Answer

Alright. Thank you!