Krishna
0

Step 1: Read the question and note down the given information.

        GIVEN:  The total number of students in 10th class = 40

                                  number of boys  = 15

                                  Number of girls  = 25

                        Form the box only one name card has to be chosen.


Step 2:  Calculate the probability that the card with the name of a girl.

              NOTE:  The number of all possible outcomes is 40

              The number of outcomes favourable for a card with the name of a girl = 25

                        \therefore P (card with name of a girl) = P(Girl) = \frac{25}{40} = \frac{5}{8}


Step 3: Find the probability that the card with the name of a boy.

          NOTE:  The number of outcomes favourable for a card with the name of a boy = 15

                           \therefore , P(card with name of a boy) = P(Boy) = \frac{15}{40}= \frac{3}{8}

                                  or

          P(Boy) = 1 - P(not Boy) = 1 - P(Girl) = 1 - \frac{5}{8} = \frac{3}{8}