The ladder forms a right triangle with the wall that has legs of 5 and 12. We need to solve for the length of the ladder, which in this case, is the hypotenuse of the right triangle. You could use the Pythagorean Theorem but there's an easier way to do this. We can use the 5 - 12 - 13 Pythagorean triple so we know that the length of the ladder is 13 m.
5 feet is equal to 60 inches. 60 inches divided by 2.5 inches per hour means it would take 24 hours for the drill to reach five feet (assuming it maintains the same rate of digging)
