In star trek, mr spock is half vulcan and half human. spock has green blood like his father and not red blood like his mother. is spock married another half human/half vulcan, then what percentage of the offspring would have red blood

Easy! make a punnet square, like this
B- dominant (green blood)
b- recessive (red blood)

          B                   b
       
B    |               |               |
       |               |               |
       |||
       |                |              |
  B  |                 |              |
       |||
(sorry for poor spacing XD)
The first 2 statistics would be BB and Bb, Pure dominant and hybrid
The second 2 would also be BB and Bb, dominant and hybrid.
Their is a 100% chance of green-blooded children, and a 50% chance of pure greenblooded children and 50% chance of "hybrid" greenblooded children.

It doesn’t show the symbol