Is it a way to adjust the duration of multiple transitions ( transition in/ transitions out) like the ability to adjust the duration of multiple selected pictures in one selection?

I can think of two ways (there may be others).

1. Drag a transition to the time line. Adjust its length. Then highlight all the clips to the right, right click to bring up the context menu and select Ripple.
2. Turn on Dynamic Length Transition icon (it to the left of the Magnet icon on the tool bar). Highlight all the clips. Press the alt key and drag the transition from the Library; moving the mouse left or right will alter all the transitions placed between the clips.
   

david hiesch:

Is it a way to adjust the duration of multiple transitions ( transition in/ transitions out) like the ability to adjust the duration of multiple selected pictures in one selection?

It can't be done on transitions already placed in the timeline. Only ripple transitions, as explained by Candive, allow it.