The tablet seems to randomly shut off when its battery is at 50%.Is this just a bug?Because my PAQ9S lasts around 3/4 hours after each charge.I'm assuming it's a miss calculation,but will it be fixed?

possible bad battery.

I called Amazon and went through a 15 min troubleshooting session with support. Since mine was only 10 months old they sent a replacement. When it happened to the replacement it was 3 years old so I had to buy a new Fire - they forums say it's the charging portal.

Since it's brand new, return it. You didn't say what type of tablet it is, but they should last for many hours on a charge.

Turned off the tablet, unplugged the charger and kept the tablet off for about 30 minute to one hour, plugged in back the charger, then turn on the tablet. After that I you might see the tablet started charging. Good Luck.

Check out the troubleshooting section in the manual.
Check your apps to see if you have any malware programs you can load and run
Samsung

the nickle cadmium battery in your tablet has developed what is know as 'battery memory' due to improper charging practices. Time to replace the battery.

A HDX should charge from the wall in about 3-4 hours.

IF you are charging it off a USB connection on a pc or laptop the charge time could be 17 hours or never if it's an old or rubbish pc or laptop.

This is true for ANY device you are using, regardless of it being Amazon, Google, Windows or any other system.

Tablets can last up to about 12 hours if you are passively reading a book on it with everything else turned off.
They will run to empty in about an hour if you are playing a fun app that eats screen and memory.

Perhaps reconsider what you want and what you want to do with your product before blaming the technology.

Same problem on my Samsung Galaxy Note 10.1 (GT-N8013) w/ OS 4.1.2

It just boots up and shuts down.

it depends.. check the battery pack maybe this cause a over charge and check first if your galaxy tablet is still part of the warranty this will help you a lot.

I had the same problem with the n810. I was using a non-oem battery and the connections were a loose fit causing the battery not able to charge.
If you take the battery cover off, hold the battery firmly in place. Connect the charger and make sure battery is charging, then press the boot button. If it boots and stays on, then shuts off when you stop holding the battery. Then you probably have a loose connection or a bad battery. Also try cleaning the connector with a pencil eraser and alcohol.
I had to wedge tthe battery in place. You can find a spare battery with a desktop charger on Ebay for around $10US.