A painter needed 3 days to paint a room. How long would it take him, working at the same rate, to paint a room twice as large (twice the width and twice the height)?
12 days because the walls would be four times as big as the first room.
If the walls are 10 ft x 10 ft, then each wall has 100 square feet. Adding the four walls makes 400 square feet to paint. Doubling the width and height of the walls to 20 ft x 20 ft means each wall is now 400 square feet, for a total of 1600 square feet to paint. 1600 ft is four times 400 square feet, thus if it took him 3 days to paint 400 square feet, it will take 12 days (or four times as much) to paint 1600 square feet.
A married couple is traveling by bus on dangerous mountain roads. Midway through their journey the bus stops for snacks and a restroom break. The couple is enjoying the postcards in the store when the bus driver curtly tells them it’s past time to leave. Fifteen minutes after, the bus is hit by a mud slide and two people are killed. The couple blames themselves for the deaths. Why?
They blame themselves because they caused the bus to be late. If they had been on time, the bus would have already passed the location of the mud slide.
Alfred and Bill are clerks at the local grocery store. Alfred can stock a shelf in 20 minutes, but Bill is new and takes 30 minutes. How long would it take for them to stock a shelf together?
