The question asks for a speed. Speed is distance covered divided by the time taken to cover the distance.
8.30 mins is a time. There is no information on the distance covered in that time. Consequently, the question makes no sense at all.
they run 18 miles per hour
11.333 (recurring) miles per hour.
About 3.4 miles per hour.
20 miles per hour
30 miles per hour
giraffes can run 35 miles per hour
That depends on how long you run for.
it runs 10 miles per hour
it runs 40 miles per hour
About 70 miles per hour.
35mils per hour
At least 6 miles per hour.