"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.