Surviving a 14-story fall is highly unlikely. The impact force and injuries sustained would be overwhelming for the human body. Broken bones, internal bleeding, and severe trauma are common and often life-threatening.
The chances of survival from a 12-story fall are extremely slim. The force of the landing and the speed at which you hit the ground make it highly unlikely to come out unscathed. You could suffer from multiple fractures, internal bleeding, and head trauma.
It's highly unlikely to survive a 15-story fall. The force and height involved make it almost certain that one would suffer fatal injuries. Maybe in very rare and exceptional circumstances with some form of intervention or cushioning, there could be a slim chance, but that's extremely rare.
Surviving a 3-story drop is extremely difficult. The speed and force upon landing are often too much for the body to handle, leading to broken bones, internal bleeding, and other life-threatening conditions.
To survive in a post - apocalyptic world as per 'can you survive story', it's all about resourcefulness. You'll have to make use of whatever is available. For example, old buildings can be turned into shelters by barricading the entrances. You can use parts of broken vehicles to make tools. You also need to be able to read the signs of the environment. If there are signs of recent human activity, it could mean a potential threat or a source of resources. Mental strength is equally important. The constant stress and danger can break a person, but if you stay strong - minded, you have a better chance of making it through.