Mathematics 4024 · O Level · Probability of combined events

Probability of combined events — practice question

(a(i))[1]

A set of $40$ children is each asked how many books they read in the previous month. Write down the mode.

(a(ii))[1]

Find the median.

(a(iii))[2]

Calculate the mean.

(a(iv))[2]

A single child is selected at random from the $40$ children. Find the probability that this child read $4$ or more books. Give your answer as a fraction in its simplest form.

(b(i))[2]

A shelf holds $10$ books. $7$ of these books are fiction and $3$ are non-fiction. Sanjay picks a book from the shelf at random, checks it and then puts it back. He then picks another book from the shelf at random, checks it and then puts it back. Find the probability that one book is fiction and the other book is non-fiction.

(b(ii))[3]

Mona takes $3$ books from the $10$ books on the shelf at random without replacement. Find the probability that exactly one of the books she takes is fiction.

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