Answer: 11.9%
Step-by-step explanation:
Given : On a stretch of Interstate-89, car speed is a normally distributed variable with
mph and
mph.
Let x be a random variable that represents the car speed.
Since , 
z-score corresponds x = 73 , 
Required probability :

[using z-value table.]
Hence, the approximate percentage of cars are traveling faster than you = 11.9%
Well lets see. if you're being specific about the rigor, then the period means that <span>cos(2Π÷3(x+α))=cos(2Π÷3(x))</span>Therefore this gives <span>2π÷3α=2π</span>so α = 3.
Hope this can help you
Probably Just The Variable