Answer:
820 cartons
Explanation:
**Note: The 12-pack carton of cola reference is not pertinent to this problem, it was put in as a descriptor, and to throw you off **
Given that there are 40 cartons on the base and 1 on the top, we know that to make a triangle display, there needs to be one less than the previous number on top:
All you need to do is start with 40, and subtract one:
40 - 1 = 39
From here you do the same thing and subtract one:
39 - 1 = 38
You can continue to do this until you have 2, and subtract 1 from it, and then add all your answers up, but if you know that you have to go one down there is no need for subtraction in work form:
40 + 39 + 38 + 37 + 36 + 35 + 34 + 33 + 32 + 31 + 30 + 29 + 28 + 27 + 26 + 25 + 24 + 23 + 22 + 21 + 20 + 19 + 18 + 17 + 16 + 15 + 14 + 13 + 12 + 11 + 10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1
All of these number added together will then give you 820 cartons as your answer