Answer: Fourth option is correct.
Step-by-step explanation:
Since we have given that
Distance traveled by Brian = [tex]4\frac{1}{4}\ miles=\frac{17}{4}\ miles[/tex]
Time taken by him = [tex]\frac{3}{4}[/tex] of an hour
So, Speed at which Brian is running fast is given by
[tex]Speed=\dfrac{Distance}{Time}\\\\\\Speed=\dfrac{\dfrac{17}{4}}{\dfrac{3}{4}}\\\\\\Speed=\dfrac{17}{3}\\\\\\Speed=5\dfrac{2}{3}\ mph[/tex]
Hence, Brian was running fast at [tex]5\dfrac{2}{3}\ mph[/tex]
Therefore, Fourth option is correct.
