The venn diagram above shows the numbers of students offering music and history in a…

The venn diagram above shows the numbers of students offering music and history in a class of 80 students. If a student is picked at random from the class, what is the probability that he offers Music only?

Correct Answer: Option D

Explanation

30 – x + x + 40 – x = 80 – 20
70 – x = 60
– x = 60 – 70
– x = – 10
∴ x = 10
Music only = 30 – x
= 30 – 10
20
P(music only) = 20/80
= 1/4
= 0.25