Question 757145
It looks like all of the students were surveyed. Otherwise,
you couldn't solve it. 
Draw three interlocking rings ( Venn diagram ) so that
there is an area in the center which is common to
all three rings.
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It's helpful to notice there are 8 categories listed and the
Venn diagram divides into 7 areas. Everything outside
the 3 rings is the last category: 
" 26 owned none of the devices"
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The area in the center is:
"68 owned an iPod, laptop and gaming system"
Now there are 6 categories left
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"193 owned an iPod and laptop"
If you subtract 68, you get 125, which is the area
( ipod + laptop ), but not ( ipod + laptop + gaming system )
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"200 owned an iPod and gaming system"
If you subtract 68, you get 132, which is the area
( ipod + gaming system ), but not ( ipod + laptop + gaming system )
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"139 owned a laptop and a gaming system"
If you subtract 68, you get 71, which is the area
( laptop + gaming system ), but not ( ipod + laptop + gaming system )
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Now there are 3 categories left
"356 owned an iPod"
Now subtract ( 125 + 68 + 132 = 325 )
356 minus 325 = 31
These 31 own an ipod and nothing else
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"293 owned a laptop"
subtract { 71 + 68 + 125 = 264 )
293 minus 264 = 29
29 own a laptop and nothing else
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"285 owned a gaming system"
subtract ( 132 + 68 + 71 = 271 )
285 minus 271 = 14
14 own a laptop and nothing else
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(a)
The number that owned exactly 2 of the devices is
( 125 + 132 + 71 = 328 )
(b)
The number that owned at least 1 of the devices is
The sum of all the areas:
( 14 + 29 + 31 + 71 + 125 + 132 + 68 = 470 )
Hope I got it