Teesha is in french club. there are 10 freshman, 12 sophomores, 15 juniors, and 30 seniors in the club. the advisor is going to randomly choose one of the members of the club to be a guide for an important visitor. find the probability that she will not choose a freshman

We know that

In French club there are
10 freshman
12 sophomores
15 juniors
30 seniors

total of the members> (10+12+15+30)=67
total  freshman> 10

so
the probability that a freshman will be chosen=10/67
and 
the probability that a freshman will not be chosen=(67-10)/67
the probability that a freshman will not be chosen=57/67---> 0.8507
0.8507= 85.07%

the answer is
the probability that a freshman will not be chosen is 85.07%