Question

Can someone please help me with this word problem? Eva and London work for a company that is responsible for grading English essays. Suppose it takes London 4 times as long as Eva to grade a batch of essays. If it takes them 2 hours working together to grade a batch of essays, how long will it take London working alone to do the same job?

Answer 1

10 hours

Explanation:

Since Eva works 4 times as fast as London, she is doing work equivalent to the work done by 4 Londons. Then all of the work is being done at a rate equivalent to having 5 Londons on the job.

If it takes 5 Londons 2 hours, then it would take one of them 5 times as long, 10 hours.

London working alone takes 10 hours to do the job.