In other space,there was once an Insect X and 20 Insect Y.With in a second,an Insect X ate InsectY,and at the same time every Insect X and every Insect Y broke up into two.Finally Insect X ate all the Insect Y.How many second did it take?

问题描述:

In other space,there was once an Insect X and 20 Insect Y.With in a second,an Insect X ate Insect
Y,and at the same time every Insect X and every Insect Y broke up into two.Finally Insect X ate all the Insect Y.How many second did it take?