For this case, the first thing you have to keep in mind is that we are in the presence of a piece function.
We have then:
For [0, 5]:
A car traveling at 46 mi / h slows to a speed of 23 mi / h in 5 seconds.
For [5, 10]:
It maintains that speed for 5 seconds.
For [10, 15]:
then slows to a stop after 5 more seconds.
In this case:
x axis: represents time
y axis: represents the speed.
Answer:
See attached image for the graphic v (t) vs t.