A hundred-pound watermelon drying from 99 to 98 percent water

A watermelon weighs $100$ pounds and is $99\%$ water by weight. After sitting in the sun it is $98\%$ water. What does it weigh now?

$50$ pounds. The dry matter stays at $1$ pound. If that is now $2\%$ of the total, the total is $\tfrac{1}{0.02}=50$ pounds.