Answer :
Since the average speed of the car is x miles per hour, then
We have to change the 90 minutes to hours
Since 1 hour = 60 minutes, then
Divide 90 by 60 to change from minutes to hours
[tex]T=\frac{90}{60}=\frac{9}{6}=\frac{\frac{9}{3}}{\frac{6}{3}}=\frac{3}{2}[/tex]90 minutes = 3/2 hours
By using the rule of the distance
[tex]d=s\times t[/tex]s is the speed
t is the time
Since s = x and t = 3/2, then
[tex]\begin{gathered} d=x\times\frac{3}{2} \\ d=\frac{3x}{2} \end{gathered}[/tex]The car can travel 3x/2 miles in 90 minutes
The answer is B