Explanation
Correct answer: B.
Choice B is correct. Let be the number of novels and be the number of magazines that Sadie purchased. If Sadie purchased a total of novels and magazines, then . It is given that the combined price of novels and magazines is $. Since each novel sells for $ and each magazine sells for $, it follows that . So the system of equations below must hold.
Subtracting corresponding sides of the second equation from the first equation yields , so . Therefore, Sadie purchased novels.
Desmos solution:
Note: n represents novels and m represents magazines in the total-price and total-item equations.
Enter in Desmos:
Reviewed and rewritten by CookSAT
Why the other choices are wrong
Choice A
Choice A is incorrect. If novels were purchased, then a total of $ was spent on novels. That leaves $ to be spent on magazines, which means that magazines would have been purchased. However, Sadie purchased a total of novels and magazines.
Choice C
Choice C is incorrect. If novels were purchased, then a total of $ was spent on novels. That leaves $ to be spent on magazines, which means that magazines would have been purchased. However, Sadie purchased a total of novels and magazines.
Choice D
Choice D is incorrect. If novels were purchased, then a total of $ was spent on novels. That leaves $ to be spent on magazines, which means that magazines would have been purchased. However, Sadie purchased a total of novels and magazines.