David can proofread 15 reports in an hour, while Armando can proofread 37 reports in an hour. If they have 400 reports to proofread, how much time will it take between the two of them?

In order to know how much time will David and Armando take, you need to write down the given and solve them with the given solution.

David - 15 reports

Armando - 37 reports

Total Reports = 52 reports in total

Total Reports in an hour = 52

Overall total reports = 400

Time to finish = ?

If you try to evaluate, if you have 50 reports in an hour with a total of 400 reports, you could have gain 8 hours by doing the reports.

So to expand more, 52 reports will be divided into 400, giving a total of 7.6

So the answer is that they will take 7 hours and a half in doing the reports.