Question

Following are the details of exam results for Math and English for a class of 100 students.

$\begin{array}{ccc}& \text{Passed Math}& \text{Passed English}\\ \text{Passed Math}& 25& 20\\ \text{Passed Math}& 35& 20\end{array}$

Find the probability that a student selected at random passed in:
1. both exams
2. exactly one exam
3. at least one exam [3 MARKS]

Answer 1

Solution: 1 Mark each

Total number of students = 25 + 35 + 20 + 20 = 100
Probability that a student passed both exams = 25/100 = 0.25
Probability that a student passed exactly one exam = (20 + 35)/100 = 0.55
Probability that a student passed at least one exam = (25 + 20 + 35)/100 = 0.8