Question

Mr. Rodriguez, a college instructor, can grade his class papers in 3 hours while it takes his assistant 4 1 2 hours. If Mr. Rodriguez graded the papers for 1 hour and then left the job for his assistant to complete, how long will it take his assistant to finish grading papers?

Answer 1

3 hours

Explanation:

Rodriguez did 1/3 of the job, so the remaining 2/3 of the job will take the assistant 2/3 of the usual time:

(2/3)(4 1/2) = 3 . . . hours

The assistant can complete the job in 3 hours.