National Geographic still sells a considerable number of copies. Its demand for the April issue is forecasted to be normally distributed with a mean of 80 and a standard deviation of 35. If the Penn Bookstore stocks 100 copies, how many copies can they expect to return to the publisher at the end of the month

29

Step-by-step explanation:

What we must do is calculate the z value for each value and thus find what percentage each represents and the subtraction would be the percentage between those two values.

We have that z is equal to:

z = (x - m) / (sd)

x is the value to evaluate, m the mean, sd the standard deviation

So for 100 copies we have:

z = (100 - 80) / (35)

z = 0.5714

and this value represents 0.7157

Which means, that of those 100 copies it is probable that they could be distributed:

100 * 0.7157 = 71.57

71 copies, so a total of about 29 (100 - 71) were being returned

option 3 . (5x + 1) - (-10x + 6)

step-by-step explanation:

option 1 :

(4x + 3) + (-9x + 4)

or 4x+3 -9x + 4

or -5x + 7

option 2

(x - 2) - (6x - 9)

or x-2-6x + 9

or -5x + 7

option 3

(5x+ + 6)

or 5x + 1 + 10x -6

or 15x -5

option 4

-4x+2x+7-3x

-7x + 2x + 7

-5x + 7

hence only option 3 did   not satisfy the given simplify expression.

your answer is b.

x = 33.9

y = 65.6

step-by-step explanation: