Answer:
21 more mugs were brought this year than last year.
Explanation:
We can solve by subtracting the initial amount of mugs from the final amount of mugs.
To find the amount of mugs hung up this year, we will use the equation: m = 12w where m = the number of mugs & w = the number of wooden hangers. The 12 represents the amount of mugs per wooden hanger.
We can plug in 3 for w since 3 wooden hangers were filled up and we would get 12(3) = m = 36 mugs
Now we subtract last year's total mugs hung up from this year's total mugs hung up.
We end up with 36 - 15 = 21