Final answer:
Matt can pack his posters and banners into 3 boxes, with 5 posters and 2 banners in each box.
Step-by-step explanation:
The student is asking about finding the greatest number of boxes Matt can use to pack an equal number of posters and banners. To solve this, we must find the greatest common divisor (GCD) of the numbers of posters and banners, which are 15 and 6, respectively. The GCD of 15 and 6 is 3, so Matt can use 3 boxes. To determine how many posters and banners will be in each box, we divide the total number of posters, 15, and banners, 6, by the number of boxes, 3. Therefore, each box will contain 5 posters and 2 banners.