Can I see the rest of the problem of number 18 please
The base angles are both equal to (180-70) / 2 = 55 degrees
and 1/2 base = 123
so we have tan 55 = a / 123 where a = altitude
a = 123 * tan55 = 175.66
Answer:
answer 4950
Step-by-step explanation:
first divide6600by 100 &multiply by 25 ans. is 1650
subtract 6600 by 1650 ans. is 4950
7 2/3 - 5 5/8 = 7 16/24 - 5 15/24 = 2 1/24
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.