121 is big enough to assume normality and not worry about the t distribution. By the 68-95-99.7 rule a 95% confidence interval includes plus or minus two standard deviations. So 95% of the cars will be in the mph range

The question is a bit vague, but it seems we're being asked for the 95% confidence interval on the average of 121 cars. The 121 is a hint of course.
The standard deviation of the average is in general the standard deviation of the individual samples divided by the square root of n:

So repeating our experiment of taking the average 121 cars over and over, we expect 95% of the averages to be in the mph range

That's probably the answer they're looking for.
Hey there!
To find the value of an angle in a triangle, you need to add the 3 angles. You have angles with 55 degrees, 65 degrees, and x degrees. Put this into an equation. The equation would be 55+65+x=180. Simplify to get 120+x=180. You need to isolate x, so subtract 120 from both sides to get x=60. So the value of x is 60 degrees.
I hope this helps!
Answer:
Not sure sorry Im really bad at this stuff
Step-by-step explanation: