So another way to look at is 7x6=__ and so when you do this you get 42. Hope this is helpful.
Answer:
They sold 750
adult tickets is 275 and...
children's tickets is 475
If we assume the club membership includes

then the blanks in the Juniors circle must be filled in with 6 and 8 (with the 8 going in the overlap with girls). The remaining blank in the Girls circle must be filled in with 12, the number of senior girls. The blank outside both circles is the number of senior boys (members who are not juniors and not girls), 16.
The angles look like

F- angles are corresponding angles.
Corresponding angles are congruent.