9.05 Probability calculations
Interactive practice questions
Sandy wants to categorise a list of $11$11 terms based on whether they are written with a $3$3, and whether they are even. If a term from the list is chosen at random, what is the probability that:
| Sandy's list of terms |
|---|
| $1,2,3,5,8,13,21,34,55,89,144$1,2,3,5,8,13,21,34,55,89,144 |
is an even number that isn't written with a $3$3?
it is written with a $3$3 or is an odd number?
is either odd or is written with a $3$3, but not both?
In their class $5$5 people play both football and tennis, $13$13 people in total play tennis, and $11$11 in total play football.
In a study, some people were asked whether they were musicians or not.
$25$25 responders said they were a musician, of which $10$10 were children. $25$25 children said they were not musicians, and $13$13 adults said they are not musicians.
A grade of $234$234 students are to choose to study either Mandarin or Spanish (or both). $134$134 students choose Mandarin and $120$120 students choose Spanish.