Question

An individual wants to bring multiple copies of two comic books to a convention this week. There are 15 copies of the comic book the individual wants to sell (S), and 8 copies of a comic book the individual wants appraised (A), with a combined weight of 49.9 oz. The individual can only fit 40 oz. of comics in a bag. If the individual brings 10 copies of the comic book he wants to sell (S), 4 copies to be appraised (A), the combined weight would be 30.2 oz. Calculate how much each comic (S) weighs.2.3 oz.2.25 oz.2.1 oz.

Answer 1

Let x represent the weight of the comic book to be sold

Let y represent the weight of the appraised book to be appraised

There are 15 copies of the comic book the individual wants to sell (S), and 8 copies of a comic book the individual wants appraised (A), with a combined weight of 49.9 oz. It means that

15x + 8y = 49.9 equation 1

If the individual brings 10 copies of the comic book he wants to sell (S), 4 copies to be appraised (A), the combined weight would be 30.2 oz, it means that

10x + 4y = 30.2 equation 2

Multiplying equation 2 by 2, it becomes

20x + 8y = 60.4 equation 3

Subtracting equation 3 from equation 1, it becomes

20x - 15x + 8y - 8y = 60.4 - 49.9

5x = 10.5

x = 10.5/5

x = 2.1

Substituting x = 2.1 into equation 2, it becomes

10(2.1) + 4y = 30.2

21 + 4y = 30.2

4y = 30.2 - 21 = 9.2

y = 9.2/4

y = 2.3

Weight of the comic(S) to be sold = 2.1 oz