1. $A$ is the event that a student, in a particular school, studies French, where $P(A)=0.4$

$B$ is the event that a student, from the same school, studies Spanish, where $P(B)=0.5$

Some students at the school study both French and Spanish, where $P(AandB)=0.18$

A student is picked at random from the students at the school.

Work out $P(AorB)$.