If it takes 10 hours to type 4 reports, we can find the time it takes to type one report by dividing 10 by 4:
Time to type one report = 10 / 4 = 2.5 hours
Therefore, it would take 2.5 hours to type one report.
To find how long it would take to type 15 reports, we can multiply the time to type one report by the number of reports:
Time to type 15 reports = 2.5 hours/report x 15 reports = 37.5 hours
Therefore, it would take 37.5 hours to type 15 reports.