Question

Rose is competing in a 400 m race.

She runs at a constant speed of 5.6 m/s for the first 100 m, then 4.6 m/s for 40 seconds.
The remainder of the race takes her 46 seconds to complete.
What is Rose's average speed for the entire race to 1 dp?

Answer 1

At first we need to find distance in the last bit
400=(100/5.6)+(4.6*40)+(46*x)
x=4.3

Now we can calculate the average
(5.6+4.6+4.3)/3=4.8

So average speed is 4.8 m/s