Question 1207374
<pre>
Put the clues in reverse order:

Of those surveyed:

79 tourists did not visit any of these theme parks
32 tourists had visited all three theme parks
77 tourists had visited both LEGOLAND and Universal Studios
100 tourists had visited both the Magic Kingdom and Universal Studios
53 tourists had visited both the Magic Kingdom and LEGOLAND
268 tourists had visited Universal Studios
250 tourists had visited LEGOLAND
A survey of 1,174 tourists visiting Orlando was taken. 

The answer to "How many tourists only visited the Magic Kingdom (of these
three)?" will be the answer to region g.

{{{drawing(300,300,-4,4,-5,4,
rectangle(-4,-3.5,4,4),
circle(0,-.5,2),
locate(-2.3,2,"a=?"),
locate(-3.5,-2,"h=?"),
locate(0,-2.7,M),
locate(-.45,-1,"g=?"),
locate(.6,.4,"f=?"),
circle(sqrt(2),sqrt(2),2),
locate(-3.5,2.5,L),
circle(-sqrt(2),sqrt(2),2),
locate(3.5,2.5,U),
locate(-1.5,.5,"d=?"),
locate(-.4,2.3,"b=?"),
locate(1.8,2,"c=?"),
locate(-.4,1.1,"e=?") )}}}

79 tourists did not visit any of these theme parks

So put h=79 outside all three circles.

32 tourists had visited all three theme parks

So put e=32

77 tourists had visited both LEGOLAND and Universal Studios

The other 77-32=45 go in region b, so b=45

100 tourists had visited both the Magic Kingdom and Universal Studios

The other 100-32=68 go in region f, so f=68

53 tourists had visited both the Magic Kingdom and LEGOLAND

The other 53-32=21 go in region d, so d=21

268 tourists had visited Universal Studios

The other 268-45-32-68=123 go in region c, so c=123

250 tourists had visited LEGOLAND

The other 250-45-32-21=152 go in region a, so a=152

A survey of 1,174 tourists visiting Orlando was taken.

The other 1174-152-45-123-21-32-68-79 = 654, so g=654

That's the answer, 654.

{{{drawing(300,300,-4,4,-5,4,
rectangle(-4,-3.5,4,4),
circle(0,-.5,2),
locate(-2.3,2,"a=152"),
locate(-3.5,-2,"h=79"),
locate(0,-2.7,M),
locate(-.45,-1,"g=654"),
locate(.6,.4,"f=68"),
circle(sqrt(2),sqrt(2),2),
locate(-3.5,2.5,L),
circle(-sqrt(2),sqrt(2),2),
locate(3.5,2.5,U),
locate(-1.5,.5,"d=21"),
locate(-.4,2.3,"b=45"),
locate(1.8,2,"c=123"),
locate(-.4,1.1,"e=32") )}}}

Edwin</pre>