Of 500 students , 200 participating in math activity , 250 participating in science activity and 50 participated in both activities , Find that a randomly selected student.

a) Will be a participant in at least one of the two activities.

b) Will not be a participant in either activity.

c) Will be a participant in exactly one activity.

My answer :

a) 0.8

b) 0.3

c) 0.5

Is my answer correct?