Question

There are three books of poetry, five history books, and four about animals on a shelf. What is the probability of choosing a book about history and then a book about animals?

Answer 1

Total number of books = 12

$P\mleft(history\mright)=\frac{5}{12}$

since one book has been taken

$P\mleft(animals\mright)=\frac{4}{11}$

The probability is then the product of both probabilities, that is:

$P\mleft(historyandanimals\mright)=\frac{5}{12}\times\frac{4}{11}$

Solving we get:

$P\mleft(historyandanimals\mright)=\frac{20}{121}$