Question

i a grup of students some are i oe or more of scool hockey,netball or swimmig teams.the diagram show
the numbers where h are i hockey team,n are in netball team nd sare i swimmig team.if tere are 21 pupil find x? what is the probabilty that pupil chose at random is i 1. hockey team only 2.at least two teams 3. exactly one team 4.the net ball team 4 3 3
2 2 1

1 x=? these numbers are in 3 circles