Update questions-ch3.md
Update questions-ch3.md
Update questions-ch3.md
Correct answers for computing the weakest precondition

There are two things you should know:

1) Note that the appearance of the left side of the assignment statement in its right side does not affect the process of computing the weakest precondition. (see PDF page 151)

2) The weakest precondition is the least restrictive precondition that will guarantee the validity of the associated postcondition. (PDF page 149)
conflict commit
Merge branch 'master' of https://github.com/qiaoshun8888/practice into qiaoshun8888-master