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Question
There are 40 students in a class of whom 25 are girls and 15 are boys. The class teacher has to select one student as a class representative. He writes the name of each student on a separate card, the cards being identical. Then she puts cards in a bag and stirs them thoroughly. She then draws one card from the bag. What is the probability that the name written on the card is the name of a girl ?
Solution
Total number of students = 40.
Number of boys = 15.
Number of girls = 25.
Let E1 be the event of getting a girl's name on the card.
∴ P(selecting the name of a girl) = P(E1) = `("Number of outcomes favourable to" E_1)/"Number of all possible outcomes"`
`=25/40 = 5/8`
Thus, the probability that the name written on the card is the name of a girl is `5/8`.
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