One day, the northwest woodworkers studio produced six times as many bookshelves as the southwest woodworking guild. if the difference in their production is 15, how many bookshelves did southwest woodworking guild produce that day?

3

Explanation:

Northwest Woodworkers (NW) produced six times the quantity produced by Southwest Woodworking Guild (SW).  That means the difference between the productions is 5 times (think NW produced 6 and SW produced 1 for example, overall, it's 6x but it's a difference factor of 5x).

Since we know the different in units was 15, we can say:

5x = 15, so x = 3

SW produced 3 bookshelves, while W produced 18. (6x as many, difference of 15).

oh my god you are going so many marks marks i don't want to give you answers sorry

answer; no individual buyer or seller has any significant impact on the market price;