Repairing joists

[stevesee]

I have two joists that have been cut short by about 14 inches. I want to marry up a new joist length to each one and then attach to the wall with joist hangers.
Question: the room spans 11 1/2 ft. How far along the length should I double up. I know the whole length would be the bestl but I don't want to take the whole floor up.

 

[tim00]

Research bolt-on's in this forum. Bolt-on a 3ft plus 14" length ie. 4ft 2ins.

 

[stevesee]

I also looked on the forums about bolts and the ones I mentioned came up, so I'll go with them.
Okay, 4ft or so doesn't sound too bad.