Question

For a drama, 3 students need to be selected out of 6 students A,B,C,D,E and F. If A is already selected, what is the probability of selecting C also?

• A. 0.5
• B. 0.2
• C. 0.3
• D. 0.4

Answer 1

The correct option is D 0.4

If A is selected, then two more students need to be selected. This can be done in ${}^5$C${}_2$ ways= 10

If C is also selected, only one more out of the remaining 4 needs to be selected.
That can be done in 4 ways.

Thus, Probability =$\frac{4}{10}$ = 0.4