Chapter 4: Kirigaoka's No.1 Student
He turned to the window beside him and saw the man with the crooked neck, staring back at him at an angle.
*Smash*
The glass was shattered to pieces when an arm punched through it and grabbed onto Akira. Akira's upper body was pulled out from the seat, but this caused the neck to be too far and the arm closer to the man.
He ripped into his arm with his teeth.
As this wasn't a vital spot, Akira was eaten alive for another couple of minutes before bleeding out from axillary and brachial arteries in his arm.
In those few minutes, Saku cried and prayed that he would not be next.
***
Day 0 - Kirigaoka Junior High School class 2-C - 9 hours earlier
Teacher Akihiro just finished writing the solution to a math problem on the blackboard. He put down the chalk and clapped the dust from his hands.
"That's it for matrices. Finish the chapter in your textbooks for the pop quiz tomorrow."
It was almost home time.
A student lifted his hand.
"Sensei."
"Hm?"
Teacher Akihiro looked up from his laptop on the standing desk.
"Ahhh yes, thank you for reminding me, Hikaru."
Teacher Akihiro had said at the start of the year that he'll prepare an advanced problem on the related math topics and that anyone who can solve it on the spot will get a 2% bonus mark-up.
A few students had the guts to take the challenge but only one passes every one of them. Since then, no one else tried.
This was one reason Hikaru was the no.1 student in Kirigaoka junior high (year 7-9) school.
"I met up with my friend from the US a couple of days ago and we came up with this problem. For this problem, you have a time limit of 5 minutes.
"A business executive who finished his business trip to Tokyo was found dead when the plane arrived in Los Angeles International Airport. The medical examiner called the time of death at 4:40 pm. Here is a list of the flights in the last 24 hours."
Teacher Akihiro handed over an A4 sheet.
The list contained the airline company, destination, departure and arrival times for 15 other countries, half of them were between Tokyo and Los Angeles.
He listed them in a long table with about 50 rows. The list was a matrix timetable and so was an obvious hint at the mathematics required.
There were no details about multi-city trips between the countries, for example, flights connecting Tokyo, Aus and LA or Aus, MNL and SFO, etc.
With only five minutes, time was of the essence.
"Passengers noted the deceased was awake for 12 hours then fell asleep in the last hour after drinking.”
Hikaru blinked.
"Find the three most likely airplane schedule he could have taken. Any questions?"
Teacher Akihiro expected that if Hikaru couldn't solve it in ten minutes, then he would ask for more time. After all, it would take himself 5 minutes to solve it and he believed that Hikaru's mathematical skills were equal or almost as good as his own. That was how much praise the teacher had for the brightest student he had ever met.
Seeing Hikaru's confident smile, he felt proud.
"Your time starts now."
Hikaru started crossing out rows on the list. After he eliminated about 20 of them, he made a table on a sheet of paper, then another one underneath it and stared at the last table for a while.
Akihiro looked at the stopwatch app on his smartwatch. Just over three minutes to go. Hikaru still had plenty of time.
"Finished."
"Huh?"
Hikaru handed a sheet of paper to Akihiro. There were a couple of lines down near the end of the page. He looked at his wristwatch.
2:01
Akihiro matched the answers to his notes.
"You got the correct answer in under 2 minutes..."
The entire class applauded.
"As expected of the no.1 student in Kirigaoka junior high."
"That was really fast!"
"Yea!"
"Maybe the question wasn't that hard... but he solved it really fast."
"Hikaru, good job. Now teach the entire class how you came up with that answer."
"Yes sensei. The first mistake, but easiest to avoid is remembering that the time of death is in L.A. and not the local time."
There was a time difference of 17 hours.
"Since the deceased was awake for 12 hours but fell asleep in the last, this meant that he was in the air for around 13 hours. Consequently, the time of death was approximately 4:40 pm and so the plane boarded at 5:40 pm. Acquiring the end arrival time eliminated some routes.
"The travel time between places weren't there, but I noticed it takes around 12 hours to travel between Tokyo and L.A. The deceased was on a flight going on for at least 13 hours, so it couldn't have been a direct flight, he must have made one or more stops.
"Of course, the business executive was most likely traveling in first class, it was unlikely he took a flight with more than one stop. He must have taken the one-stop flight because there weren't any other options but ignoring realism, I had to find possible fly routes within the parameters. The fastest way was to make an adjacency matrix."
Hikaru held the sheet of paper and pointed to the matrix with binary numbers, ones and zeros.
"Then replace the ones with inequalities in linear equations, since A is an M-matrix, multiply the matrix with inverse A to solve the equations and then manually check the solutions. That's how I came up with the three answers."
The entire class was dead silent.
"Now that you found three solutions, which out of the three do you think was most likely?"
"I think it depends on the motive of the killer or the people behind them."
"Hoh."
"If it was a serial killer, the killer was probably going on for something theatrical or poetic, like sending a soul to the city of angels."
"Hmm"
"However, maybe a rival organisation hired an assassin to kill him. An excellent spot to do that would be through this route. Tokyo - Manila Ninoy Aquino International Airport - L.A. Whether it was to protect the assassin in his turf or that assassins are cheaper to hire in the Philippines. Maybe both."
"Mmmmm"
"Sensei."
"Hm?"
"Is this an actual case?"
Gifts
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received Weekly Power Status
-- Power
Ranking 
-- Power
stone