"When he returned at 9 PM, the hotel owner saw him, and the receptionist didn't mention him leaving his room afterward." I crossed Person B off the list and said, "I agree. Since he's on the first floor, both the owner and receptionist would've noticed him leaving. He's in the clear."
Carl pondered aloud, "So, the culprit is most likely one of the remaining people. What's next?"
Seeing that Lana had taken a breather, I decided to take the lead. She had handled the first two stages of deduction, so it was my turn now. "Among the remaining suspects, two people's statements stand out for being straightforward: the receptionist and Person E."
"The receptionist only confirmed the owner's account and handled a single room service request—nothing to question there. Person E, on the other hand, called for room service multiple times in a consistent pattern: lunch, dinner, and a late-night snack."
"Looking at all the testimonies, we can cross-reference the guests' requests with the hotel staff's accounts. Here's what we know: the owner handled several requests from Person E, including one at 10 PM, and the receptionist managed one more at 11 PM."
"From the guests' side: Person A called for room service once at 10 PM, which lines up with the owner's record. Persons B, C, and D didn't request room service, though Person D saw staff near Person A's room when he went to the pool around midnight."
"Person E ordered three times: for lunch, dinner, and a late-night snack. If we assume all of Person E's requests align with the owner's account, we have only one extra sighting—at midnight, which Person D witnessed."
Lana's eyes sparkled as she looked at me, her voice filled with admiration. "Exactly! By analyzing the room service clues, we can eliminate the receptionist, Person E, and the owner. That leaves just Persons C and D."
Danny, Janice, and Carl stared at us blankly for a moment, then exclaimed, "That makes sense."
I let out a breath, crossing off the remaining names until only C and D were left. "Timewise, Person C checked in around midnight, while Person D went to the pool at midnight. Location-wise, one is on the fourth floor, and the other on the third floor—so both remain suspicious. Alone, it's hard to pinpoint who the killer is."
I smiled confidently. "But if we combine the details we've gathered, one of their statements reveals a slip."
Danny and the others looked confused, but I turned to Lana, who was deep in thought. Suddenly, her eyes widened, "Could it be...?"
"Exactly!" I interrupted, continuing my explanation. "Only the owner and these two mention Person A, but only one of them reveals knowledge only the killer would have: Person A's time of death."
I crossed off Person D and circled Person C, grinning. "Person C claimed he was packing his luggage when Person A died, but the police only discovered the time of death after questioning everyone and consulting the forensic report. If Person C isn't the killer, how could he possibly know when Person A died? What do you think, Lana?"
"House is absolutely right." Lana beamed. "If this were just a single clue, I might hesitate, but after the process of elimination and cross-referencing, I'm convinced Person C is the killer." As soon as she finished, we heard a click from the door in the corner.
It seemed our deduction was correct; we had cleared the test. But judging by the quick response, it felt like someone was watching us the whole time. Carl clapped me on the shoulder, grinning. "Nice job, House! Quick thinking! And you too, Lana—spot on."
Danny and Janice chimed in with praise as well. I humbly waved them off. "Just doing my part. Lana's insight with the cross-referencing was what sparked the idea."
Lana shot me a playful glance and said, "Your 'small contribution' is more like a gold brick, House. You've got quite the sharp mind."
I chuckled modestly, observing everyone's reactions. It looked like everyone was taking it in stride, and I was relieved to see that Carl, who I'd worried might be competitive, didn't seem annoyed by my moment in the spotlight. Fortunately, he seemed like a straightforward guy.
Not that I was being overly paranoid, but this environment was unsettling. Building a foundation of teamwork and trust could prove useful in the trials to come.
Although… maybe my scheming was just as bad as my paranoia. Well, that's the curse of having too many thoughts.
———
We entered the second room, which was larger than the previous one—around forty square meters. At the center were two stone platforms, raised about an inch above the ground and three meters apart. A nearby table held a set of small balls, paper, a pen, and an electronic scale.
One glance at the setup, and I knew what was coming: a classic puzzle. Lana picked up the instruction sheet on the table and read it out loud, "Out of twelve balls, one has a different weight. Identify which one is different, and determine if it's lighter or heavier. You may use the scale up to three times. Once you've confirmed your answer, it cannot be changed. After that, place the unique ball on one platform and the remaining balls on the other. The difference in total weight between the platforms must not exceed five pounds."
I frowned. This requirement was… tricky. I picked up one of the balls, which was about the size of a fist, and could tell it had some heft—probably a pound or two.
Hold on, this puzzle is theoretical, but in real life, there could be minor weight differences… Carl realized this too and muttered with a serious look, "This… is tougher than it looks."
Lana nodded, "Yes, it's a classic math puzzle. By gradually weighing the groups, you isolate the unique ball. I solved it once in school, but I can't remember the exact method anymore."
After a moment of frustrated thinking, she sighed, "No good, I can't recall the steps. Math has never been my strong suit."
Seeing me glance at her and Janice, Danny quickly shook her head. "Both of us are in the humanities track, so… math really isn't our thing."
That left Carl, so I looked at him. "Brother Carl, you're a software engineer; you're supposed to be a math whiz, right?"
Carl chuckled nervously, scratching his head. "I remember a bit, but I'd rather not make any mistakes. House, do you have any ideas?"
Seeing everyone's hopeful expressions, I nodded and said, "I think I remember the general solution. Let's go through it together."
Internally, I sighed. 'Seriously?' How could all of them struggle with this? Even Lana had forgotten… though, to be fair, being surrounded by people too smart might be just as risky in this situation. I picked up the pen and labeled each ball with a number.
Then, I carefully weighed each one by hand. "Okay, here's the deal. The weighing puzzle is usually a purely theoretical problem—meaning you're given conditions that allow you to solve it through math alone. But in real life, if the difference isn't minuscule, you can actually tell by feeling them one by one."
Lana took ball number 10 from me, nodding. "True. This ball is heavier. With weights like these, even a slight difference of a few grams would be noticeable."
"Right, but I just compared all the balls and couldn't find any difference by hand… so that's out. Maybe these are some high-tech weights that only the scale can measure accurately. Alright, let's go with the standard approach." I took out balls 1 to 8. "We'll divide them into three groups: Group A with balls 1-4, Group B with balls 5-8, and Group C with balls 9-12. We'll weigh Group A against Group B first."
"If the result balances, that means these eight balls are the same weight, and the unique ball is in Group C. Sound good?" Everyone nodded, following the logic.
"If Group A is heavier or lighter than Group B, then we know Group C has no unique ball, and it's between Groups A and B. Alright, here goes." I placed balls from Groups A and B on each side of the scale.
"Balanced! So, it's in Group C." Carl blurted out. I nodded, removing the balls from the scale and setting out Group C.
"Alright, for our second weighing, let's pick any two from Group C—how about balls 9 and 10. If they balance, neither is unique, so it has to be ball 11 or 12." Lana clapped her hands excitedly, "Yes! Once we know which ball is unique, we can compare it to a normal ball to tell if it's heavier or lighter."
I nodded and placed balls 9 and 10 on the scale. The 9th ball side dipped lower.
"Unbalanced. The unique ball is one of these two!" Danny's face lit up in understanding, her expression adorably triumphant. "Exactly. So now we'll set aside one of them—9, in this case—and pick any regular ball to compare."
I grabbed ball 5 at random and placed it on the other side, watching as I grabbed ball 5 at random and placed it on the other side, watching as the scale dipped toward ball 9.
"Ball 9 is the unique one—it's heavier. Nice job, House!" Carl cheered.
After accepting their praise, I wrote down our answer on the paper and then, feeling a bit confused, said, "The instructions mention weighing it again after writing our answer and standing on the platforms with the balls. But these two balls feel identical in weight…"
I placed balls 9 and 5 on the scale again, and suddenly the electronic display beneath it lit up, revealing, "2 pounds - 1 pound."
Ah, I see now. Stroking my chin thoughtfully, I realized that the total weight of these balls was 3 pounds. The unique ball was double the weight of a regular one. But somehow, when I felt it earlier, I hadn't noticed any difference—was there some internal tech in these balls that made them feel the same weight?
"So, when we stand on the platform, we calculate ball 9 as weighing 2 pounds?"
"Alright, last step: standing on the platforms," I said, glancing at everyone. "What's everyone's weight? Uh, no need to be shy—accuracy is key here."
Carl spoke up first, "I'm around 72 kilograms, I think? Last time I checked was more than six months ago, but I don't think it's changed much."
He looked slim, but he was heavier than he seemed—impressive. Lana, without hesitation, responded, "I'm exactly 54 kilograms; I weighed myself this morning."