
Bag A contains 8 Red Pens, ‘X’ Blue Pens, and 7 Black Pens. The probability to pick Blue pen at random is 2/5. Another Bag B contains ‘X-4’ Red Pens, ‘X-5’ Black Pens and 5 Blue Pens. If two Pens are picked one after the other from Bag B at random then what is the probability for the Pens to be Blue?
\( \frac{1}{21} \)
\( \frac{1}{12} \)
\( \frac{1}{8} \)
\( \frac{1}{4} \)
\( \frac{1}{2} \)

Important Questions on Counting Principles

In a college, of the girls and of the boys took part in a social camp. The total number of students in the college took part in the camp is:











There are defective items in a sample of items. One item is drawn at random. The probability that it is a non-defective item is:




Six persons go for an interview. What is the probability of selection of and in the interview?



