Usually 12 volt negative ground.
Usually 6v, can be 12v.
It should be 12 volt.
If it is a model from the last fifty years it is a 12 volts battery.
You will need a voltmeter. Hook the red cable to the + post and the black cable to the - post and it will show the voltage.
If both batteries are of the same voltage (12 or 6) yes, you can use the charger. make sure that they are of the same voltage.
I assume you mean a car battery. Yes, you can jump your lawn tractor with a car battery, following the usual precautions for jumping any vehicle.
Although it really depends on the model, most are 12V.Do You Have The Old battery how many cells does it have,most 6volts have 3cells and 12volts have 6.It all depend on the tractor some use a motorcycle battery.
weak battery?
I usually do over night.
Yes,its attached to red wire on battery
It uses a 12 volt lawn mower engine battery.
Yes, a lawn tractor can be jump started with a car battery, in the same manner as another car can be jump started.