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.
Answer:
8cm and 9cm
Step-by-step explanation:
because for the triangle to work you need the other two other sides when added together needs to be greater then 13
Answer:
30=8x
Step-by-step explanation:
lizabeth cant climb for 4.5 hrs because if you divide 30 by 8 you get 3.75. so Lizabeth can climb for 3.75 hrs using only her $30 gift card
Answer:
Sweater costs 56.00
To calculate the discounted price of the sweater
56 * (30/100) = 16.8
We used (30/100) to find out the 30 percent of the sweater which will be on discount/reduced.
56-16.8=39.2 is the discounted price
Then we subtract the amount of discount from the original price of sweater to find out the discounted price.
Step-by-step explanation: