Answer:
77
Step-by-step explanation:
Answer:

And the best answer on this case would be:
b) m = 4.635
Step-by-step explanation:
Let X the random variable of interest and we know that the confidence interval for the population mean
is given by this formula:

The confidence level on this case is 0.9 and the significance 
The confidence interval calculated on this case is 
The margin of error for this confidence interval is given by:

Since the confidence interval is symmetrical we can estimate the margin of error with the following formula:

Where Upper and Lower represent the bounds for the confidence interval calculated and replacing we got:

And the best answer on this case would be:
b) m = 4.635
12×40 is 480 that the answer
Answer:
c.
Step-by-step explanation:
From the last row in the matrix z = 1.
From the second row:
y + 5z = -4
y = -4 -5(1) = -9.
From the first row:
x + -1 = -3
x = - 3 + 1
x = -2.
$0.85
38.25/45= .85
TO CHECK
.85 times 45 equals 38.25