Question

Jacob takes 3 4 h to fill one shelf at the supermarket. Henry can fill the shelves in half Jacob’s time. There are 15 shelves. Henry and Jacob work together. How long will it take to fill the shelves? Justify your answer.

Answer 1

3 3/4 hours

Explanation:

If Henry can fill 2 shelves in the time it takes Jacob to fill one, working together they can fill 3 shelves in 3/4 hour, an average rate of 1/4 hour per shelf. It will take them 15 times 1/4 hour to fill 15 shelves.

Henry and Jacob working together can fill 15 shelves in 3 3/4 hours.