Answer:
a)

Z = -1.58 means that a reading speed of 340 wpm is 1.58 standard deviations below the mean reading speed.
b)

Z = 0.67 means that a reading speed of 475 wpm is 0.67 standard deviations above the mean reading speed.
c)

Z = -0.25 means that a reading speed of 420 wpm is 0.25 standard deviations below the mean reading speed.
d)

Z = 2.92 means that a reading speed of 610 wpm is 2.92 standard deviations above the mean reading speed.
Step-by-step explanation:
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The z-score measures how many standard deviations a measure X is above or below the mean.
In this problem, we have that:

a. 340 wpm



Z = -1.58 means that a reading speed of 340 wpm is 1.58 standard deviations below the mean reading speed.
b. 475 wpm



Z = 0.67 means that a reading speed of 475 wpm is 0.67 standard deviations above the mean reading speed.
c. 420wpm



Z = -0.25 means that a reading speed of 420 wpm is 0.25 standard deviations below the mean reading speed.
d. 610wpm



Z = 2.92 means that a reading speed of 610 wpm is 2.92 standard deviations above the mean reading speed.
Differentiate both sides with respect to <em>x</em>, using the chain rule for the sine term:


Solve for d<em>y</em>/d<em>x</em> :


So those two consecutive whole numbers will be 6 and 7.
For this, all you have to do is create equations where all you have to do is change the x value. The equation for gym A would be 35 + 42x, where x is the number of months he has the membership, and the first number is the initial fee. The equation for gym B would be 65 + 36x, following the same rules. Now all you have to do is set both of these equations equal to each other:
65+36x=35+42x
Solving this equation results in x=5, which means that he has to have the memberships for 5 months for them to be equal. Now just plug that in to one side of the equation to get the amount he has to spend:
65+36(5) = $245
N+4=13
-4 -4
n = 9
the sum of a number(n) and 4 that is no larger than 13 is 9