I don't why you put -+ but I will go ahead and assume that it is -2.
4-+6
I think it is saying 4 - positive 6 but I'm guessing.
Y=40x+100 and the second question is y=1.69x
The answer is simply C.$2.50
Answer:
The value of the test statistic is -2.64.
Step-by-step explanation:
The test statistic is:

In which X is the sample mean,
is the expected(claimed) mean,
is the standard deviation and n is the size of the sample.
An automobile manufacturer claims that its van has a 40.3 miles/gallon (MPG) rating.
This means that 
After testing 250 vans, they found a mean MPG of 39.9. Assume the standard deviation is known to be 2.4.
This means, respectively, that:

So



The value of the test statistic is -2.64.
The answer is 90 + 45 because BOC is a right angled triangle where angle BOC is 90 and angle BOK is 45 because 90 ÷2. A OK Is a right angled triangle so angle AOB is 90 as well so to find angle AOK we plus 90 and 45 which is 135 degrees.