He needs 6 more hot dog buns. You just simply subtract 12 from 18.
If you call x the total value of the sales, the sale over 12,000 will be: g(x) = 12,000 - x.
And the commission is 4.1% of that = 0.041 * (12,000 - x) = 0.041 * g(x)
So, if f(x) = 0.041x, to calculate the commission you first have to calculate g(x) = 12,000 - x, and the f(g(x))=0.041[12,000 - x].
Which leads you to the solution for the commission as [f o g] (x) = f (g(x)) = 0.041 (12,000 - x).
Answer: [ f o g] (x)
Less than 3 is about 10.75% and greater than 13 is about 6.18%.
To find these percents, you need to find the z-score for each value. Then, use your table to find the correct percent. Be sure to find the side above 13 when you use your chart.
For less than 3:
(3 - 7.45) / 3.6 = -1.24 = The percent below this is 0.1075
For greater than 13:
(13 - 7.45) / 3.6 = 1.54 = The percent above this is 0.0618
25% of 150 = 37.5
700% of x = 37.5
x = 5.35714285