Can someone me figure this one out?

How can you find the conditional probability of a given b as the fraction of b’s outcomes that also belong to a, and interpret the answer in terms of the model? i just need a good explanation

Which elements in the set below are integers? 12, –3⁄4,√ 25 , –7, √ 5 , 14⁄7, 9 a. 12, √ 25 , –7, 9 b. 12, √ 25 , –7, 14⁄7, 9 c. –3⁄4, 25 , √ 5 ,14⁄7 d. 12, –7, 9

An arc subtends a central angle measuring 7pi/4 radians what fraction of the circumference is this arc?