Question

Monica runs on a treadmill at an average speed of 7.5 miles per hour for 15 minutes. If, the next day, she runs the same distance at a speed of 8 miles per hour, what is the average time taken?

Answer 1

15 minutes * 1 hour/60 minutes = 0.25 hour

Total distance first day = avg speed first day * time first day = 7.5 miles/hour * 0.25 Hour = 1.875 miles.

Total distance on first day is the same as the distance on the second day.

Total distance first day = total distance second day = 1.875 miles

For second day:
Total distance second day = avg speed second day * time second day. 
1.875 miles = 8 miles/hour * time second day
Time second day = 1.875 miles / (8 miles/hour)
Time second day = 0.234375 hour * 60 min / 1 hour ... convert back to minutes
Time second day = 14.06 minutes

So the answer is: 14.06 min.

Hope this helped! c: