Venn Diagram and 2 other related questions HELP ME PLEASE. 10POINTS

I have this but i really can't remember how to do this sum :

A survey was conducted among 40 tourists. The results were :
28 visited Antigua (A), 30 visited Barbados (B), 3x visited both A and B, x visited neither A nor B .

i) Draw a Venn Diagram showing the above information. (Could u please tell me what type and how do i put in a venn diagram and the type of venn diagram or describe the venn diagram for this speceific sum and please tell me how do u represent the information as pertaining to calculations etc.)

ii) Write an expression, in x, to represent the TOTAL number of tourists in the survey.

iii) Calculate the value of x

Please help me. i really need help. POST YOUR QUESTION and i'll answer it and plus the best answer gets a 10POINTS AND in your answer, you could request for me to add u as a contact or fan

visited Antigua only: 28 - 3x, and visited Barbados only: 30 - 3x and the common is 3x and the rest are x
we know that the total is 40 so.. (28 - 3x) + (30 - 3x) + 3x + x = 40
expression in x: 58 - 2x = 40 ---> 2x = 18 ---> value of x = 9

the venn diagram would be like this one: http://www.scholastic.com/teacher/images/articles/l/lessonplans_graphicorg_images_venndiagram.jpg the inner part will be 3 * 9 = 27... A only will be 28 - 27 = 1... B only will be 30 - 27 = 3 and out of the circles will be 9
(you can write all that in terms of x if needed)

A survey was conducted among 40 tourists.
The results were :
28 visited Antigua (A),
30 visited Barbados (B),
3x visited both A and B,
x visited neither A nor B .
i)
Draw a Venn Diagram showing the above information.
A to represent those who visited Antigua and
B to represent those who visited Barbados;
(ab) to represent those who visited both; and
(--) who visited neither A nor B.

ii)
Write an expression, in x,
to represent the TOTAL number of tourists in the survey.
(A + B) - (ab) + (--) = 40

iii)
Calculate the value of x
A + B) - (ab) + (--) = 40
58 - 3x + x = 40
2x = 18
x = 9