Answer :
In order to find the time spent in the race, we need to use the following formula:
[tex]\text{average speed}=\frac{\text{distance}}{\text{time}}[/tex]If the distance of the race is 100 miles, and the average speed is 143.8683 mph, we have that:
[tex]\begin{gathered} 143.8683=\frac{100}{\text{time}} \\ 143.8683\cdot\text{time}=100 \\ \text{time}=\frac{100}{143.8683} \\ \text{time}=0.695 \end{gathered}[/tex]So the time spent by the winner is 0.695 hours