Answer: Scott - 18, Kaitlin - 9, Bill - 54
Explanation:
Let's view this as units. There are a total of 81 units. If we solve for Scott's orders:
Kaitlin served 9 fewer orders than Scott. We add 9 to 81 --> 9 + 81 = 90.
Now if we view Scott's orders as one unit:
Scott - 1 unit
Kaitlin (after adding 9) - 1 unit
Bill - 3 units (he served 3 times as many orders as Scott)
In total there are 3 + 1 + 1 = 5 units.
90 / 5 = 18.
Therefore, Scott served 18 orders.
18 - 9 = 9.
Kaitlin served 9 orders.
18 x 3 = 54.
Bill served 54 orders.
And to check our answer, 54 + 18 + 9 is 81.