The kind of logical fallacy which is being committed in this argument is a popular appeal. Popular appeal is a kind of logical fallacy which uses the popularity of an occurrence to prove its truthfulness. Due to the common sense that predominates which occurs due to premise's popularity, it is believed to be correct or valid.
For instance, in the above situation, because everyone passed the exam, the other person's capability is also equated with others hence, expecting to pass the exam due to the prevailing premise.