Question

please help this ones pretty tough...
The list price of a book is $15. But if more than 12 copies are purchased, then the price per copy is reduced by $0.20 for every copy above 12. This is, $14.80 per copy for 13 copies, $14.60 per copy for 14 copies, and so on.
Which of the following is the rule for this function p(x)?

Answer 1

A.

Answer 2

B.

Answer 3

C.

Answer 4

is much better to show it in 1 graphic, than scattered over 4 or so pictures

Answer 5

D.

Answer 6

it was impossible to save them all together sorry for the inconvenience

Answer 7

so, let's take a look

from 1 - 12 books, you pay regular retail price
\(\large $15\ if \ 1\le x \le 12\)
for the 13th book and above, you pay .20 less per unit
so 13-12 1 unit, 0.20 less
so 14-12 2 units, 0.40 less
so 15-12 3 units, 0.60 less

so \(\color{blue}{15 - 0.20\times unit}\) for units above the 12th one

so, which one do you think?

Answer 8

either b or c?

Answer 9

b or c, so, which one would be?

<rolling drums>
<profuse sweat and anxiety>
<biting nails>

Answer 10

oh actually c?

Answer 11

what's wrong with b?

Answer 12

your adding 15+.2 instead of subtracting

Answer 13

yep, it's c then :)

Answer 14

thanks:)

Answer 15

yw