I am now wiser for how tricky the DS questions in this competition are, and not trusting these to be anything but tricky, I believe, really helped me with this one!
So, we have 7 agents working during an evening shift. 28 customer tickets were assigned - this number, is the total such tickets assigned, divided among 7 agents (an average of 4 tickets, if you may).
Also, each ticket to exactly one agent just means there's no overlaps in tickets. Noted.
We need to see if did each agent receive at least 1 ticket - or did, even one of then, spend a day chilling without any assignments?
Simple stem, tricky question, let's go!Statement 1: Each agent was assigned a different number of tickets.
Key realization: 0 is also a number.
Now, if we assign each agent the lowest possible different numbers without considering the 0, we have exactly 28.
1 + 2 + 3 + 4 + 5 + 6 + 7 = 28.
But if, say, 1 of the agents takes 0 tickets, then too 28 is achievable.
0 + 1 + 2 + 3 + 4 + 5 +
13 = 28.
Two possible, results, hence Statement I alone IS NOT SUFFICIENT.Statement II: The agent assigned the highest number of tickets was assigned 7 tickets.
Key realization: We no longer know that each agent was assigned a different number of tickets.
This means, plenty of combinations of 28 are possible. It could be 0 + 0 + 3 + 6 + 6 + 6 + 7 = 28; or 0 + 0 + 5 + 5 + 5 + 5 + 7; anything really.
Multiple results. Hence Statement I alone IS NOT SUFFICIENT.Let's take two statements together:
We know that each individual is assigned a different number, and the largest number of these is 7. So, we can only go backwards. We saw above that 1 + 2.... + 7 = 28, so we have that as a lock-in.
Now, here's the thing, if we assume any of these numbers to be a 0, the other 6, while being different, will never add up to 28. 0 + 2 + 3 + 4 + 5 + 6 + 7 = 27; now, if you replace any other number, we'll just derive a number that's lesser than lesser than 28, never exactly 28, which the number needs to be.
Hence, Both Statement I and Statement II - Answer is C Bunuel