Once upon a time there were seven dwarfs who were all brothers. They were all born two years apart. The youngest dwarf is seven years old. How old is his oldest brother?
The oldest brother is 19 years
If 3 cats can kill 3 rats in 3 minutes, how long will it take 100 cats to kill 100 rats?
In a lake, there is a patch of lily pads. Every day, the patch doubles in size. If it takes 48 days for the patch to cover the entire lake, how long would it take for the patch to cover half the lake?
The patch doubles in size every day and so on the 47th day the patch will be half the size it is on the 48th day