Problem 2

 

Assume a watermelon weighs 100 lbs and contains 99% water.  It is left out in the hot sun so that some water evaporates until the watermelon contains only 98% water. What is the weight of the watermelon then?

 

[Problem submitted by Juergen Pahl, LACC Professor of Mathematics,]

 

 

Solution for Problem 2:

 

Let  be the amount of water lost due to evaporation.  Then the amount of water left in the watermelon is

 

 

50 lb of water had evaporated, and therefore the weight of the watermelon had dropped to 50 lb.