Question

Out of forty students, $14$ are taking Reading composition and $29$ are taking chemistry. If four students are in both the classes.What is the probability that a randomly chosen student from this group is taking only the chemistry class?

• A. $0.4$
• B. $0.6$
• C. $0.45$
• D. $0.8$

Answer 1

The correct option is B $0.6$

29 students take chemistry and four students take both reading composition and chemistry.

Thus, the number of students taking only chemistry is $29-4=25$

14 students take Reading Composition and four students take both reading composition and chemistry.

Thus, the number of students taking only Reading composition is $14-4=10$

1 student did not take anything.

Total students = $10+25+1+4=40$

When a student is randomly chosen, probability that he has taken only chemistry becomes $\frac{25}{40}=0.625\approx 0.6$