Answer: C is our answer.
The first thing that we can do is divide the known number of books into the price that they sold for.
Our equation would be 89.25 divided by 7, which is 12.75. This means that one single book is 12.75. We can look at the charts and point out where one book is 12.75, that is both A and D. While Chart B and C have 7 books for 89.25 which we know is correct.
Lets look at chart D.The next part we can solve is the price of 2 books. 12.75 x 2 is 25.50, so we can mark question B incorrect since two books are 25.50 not 13.75.Chart B is incorrect because 14 books is double 7, so it should be twice as much as 89.25, which we should know 90 dollars is not two times as much 80. Chart A is incorrect because 11 x 12.75 is 140.25, while the chart reads as 22.75.
Now lets look at chart C. Next we can solve the price of 8 books. 8 x 12.75 is 102. Then we solve for 9 books. 12.75 x 9 is 114.75, which means that C is correct.
I hope this helped & Good Luck <3!!