Question

There are 15 boys and 20 girls in a class. what is the probability that-
i) a boy secures 1st position in class.
ii) a girl secures 1st position in class.

Answer 1

Answer:

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Answer 2

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$Total \: \: no. \: \: of \: \: outcomes \: \: = Total \: \: no. \: \: of \: \: girls + Total \: \: no. \: \: of \: \: boys \\ ⟹ 20 + 15 \\ ⟹ 35 \\ \\ {\boxed{\rm{\red{P(E) =\frac{Numbers \: of \: trials \: in \: which \: the \: event \: happened}{Total \: number \: of \: trails}}}}} \\ \\ i) Probability \: \: of \: \: a \: \: boy \: \: secures \: \: 1st \: \: position \: \: in \: \: class \\ \\ {\rm{\green{P(E) = \frac{\cancel{15}^{3}}{\cancel{35}^{7}}=\frac{3}{7}}}} \\ \\ ii) Probability \: \: of \: \: a \: \: girl \: \: secures \: \: 1st \: \: position \: \: in \: \: class \\ \\ {\rm{\green{P(E) = \frac{\cancel{20}^{4}}{\cancel{35}^{7}}=\frac{4}{7}}}}$