They are both correct in their computation
(28.5-28.5(.3))+.1(28.5-28.5(.3))=$21.945
28.5(.7)(1.1)=$21.945
And since they each have $22 to spend, they have enough to purchase the book.
Answer:

Step-by-step explanation:
The conic form of the equation for a sideways parabola is
(y - k)² = 4p(x - h)
The focus is at (h + p, k)
The equation of Samara's parabola is
(y - 3)² = 8(x - 4)
h = 4
p = 8/4 = 2
k = 3
h + p = 6
So, the focus point of the satellite dish is at

That is the Identity Property of Addition.
If it is adding and the whole number stays the same it is Identity Property of Addition.
If it is multiplying then it would be the Identity Property of Multipulcation. For example for this problem it would be 6x1 in multipulcation in which the whole number would stay the same.
Here are descriptions of all the properties:
https://wikis.engrade.com/mathproperties1
Answer:
3285
Step-by-step explanation:
5x3144=15720
3990
15720+3990=19710
19710/6=3285