How many cats can catch 100 rats in 100 minutes if 5 cats can catch 5 rats in 5 minutes?

I assume those 5 cats are working simultaneously. If you give those 5 cats 20 times the minutes (5min x 20 = 100min), they are gonna catch 20 times the rats (5 rats x 20 = 100 rats). So 5 cats can catch 100 rats in 100 minutes.