When Rohan was 9 years old he hammered a nail into a tree to mark his height. Ten years later, Rohan returned to see how much higher the nail was. If the tree grew by four inches each year, how much higher would the nail be?
You are driving a car. On your right is a steep cliff. In front of you there is a horse and right behind is an elephant, both of which travel at your own speed. On your left there is a fire truck blocking you. How do you stop your car?
