"If 100 kg of watermelon can produce 1 kg of watermelon seeds, then buy 2000 kg of watermelon, eat melons and keep seeds, and exchange seeds for melons." The topic is not finished. Do you want to add it as follows:

"If 100 kg of watermelon can produce 1 kg of watermelon seeds, then buy 2000 kg of watermelon, eat the seeds, replace the seeds with melons, and replace the melons with seeds. * * How many kilograms of watermelon can I eat in the end? "

The following solutions:

Eating melons for the first time: 2000 kg, getting melon seeds 2000/ 100* 1=20 kg, and getting 20 kg watermelon in exchange.

Eat melon for the second time: 20kg, get melon seeds 20/ 100 * 1 = 0.2kg, and get 0.2kg watermelon through exchange.

Eat melon for the third time: 0.2kg, get melon seeds 0.2/100 *1= 0.002 kg = 2g, and can't change any more.

So the total number of melons eaten three times is: 2000+20+0.2 = 2020.2 Jin.