Hypothsis Testing

#1
In a training center, a new strategy was implemented. After the implementation of this new strategy the training center claimed that on an average 80% of the students passed. In order to find out whether this claim can be justified, we take a random sample of 30 students and see that 60% of the students passed. Do we have sufficient evidence to accept the 80% claim?
Need help to solve this question.
 
#3
I m new to statistics.so,which probability distribution should i use here.I want to use normal distribution but what shuld be the std deviation?