word problem

At the beginning of a class period, half of the students ina class go to the library. Later in the period, half of the remaining students go to the computer lab. If there are 8 students remaining in the class, how many students were originally in the class?

i am not even sure where to begin.

32 i got it

You're not going to share?

What if 19 students (instead of 8) are left?