The above is a pictograph that represents selected results from a surv

Question

https://gmatclub.com/forum/download/file.php?mode=view&id=74228 The above is a pictograph that represents selected results from a survey of steelworkers at the Cochran Central Steel Mill. Each symbol represents 50 workers in a sample of 2,000. Refer to this pictograph and use the dropdown menus to complete each statement in accordance with the information given above. If one worker is selected at random from the surveyed 2,000, the chance that the worker earns less than $30,000 a year or has a college education or both is GRAPH_1_PLACEHOLDER If one worker is selected at random from the surveyed 2,000, the chance that the worker will both earn less than $30,000 a year and have a college education is GRAPH_2_PLACEHOLDER 2.jpg

PMitchell · Accepted Answer

Foo overlapping sets, I like to always translate to a table, takes 15 secs.
Here:
Let's stick with the number of symbols instead of going back to the total number of people.

(blank) // College // No College // Total
-30k // 16 // 6 // 22
+30k // 12 // 6 // 18
Total // 28 // 12 // 40

So, first question:
Number of people with college education: 28
Number of people who make -30k: 22
Number of people who have both (need to be substracted since counted twice): 16
Total: 28+22-16= 34

So 34/40=17/20

Second question:
It's quite immediate, the number is at the crossing of column "College" and "-30k", so 16
Total: 16/40=2/5

Gemmie · Answer

Each symbol represents 50 workers in a sample of 2000
=> There are 40 symbols

If one worker is selected at random from the surveyed 2,000, the chance that the worker earns less than $30,000 a year or has a college education or both is   
 
 Earn less than $30k 
 Has a college education 
 Both  
=> Remaining is those both earn more than $30k and No college education
=> 6 symbols
=> % those both earn more than $30k and No college education =  \frac{6}{40} = \frac{3}{20}

=> % those earning less than $30,000 a year or having a college education or both:  1 - \frac{3}{20} = \frac{17}{20}

If one worker is selected at random from the surveyed 2,000, the chance that the worker will both earn less than $30,000 a year and have a college education is   
 
 Earn less than $30k 
 Have a collge education  
=> Those symbols not in any circle
=> 16 symbols
=> % =  \frac{16}{40} = \frac{2}{5}

vasu1104 · Answer

>=30000 
 <30000 
 total 
 
  no college 
 300 
 300 
 600 
 
  college 
 600 
 800 
 1400 
 
  total 
 900 
 1100 
 2000

s-1
p(<30000) + p(college) - P(<30000 & college)
1100/2000 + 1400/2000 - 800/2000
1700/2000
17/20

s-2
p(<30000 & college)
800/2000
2/5

The above is a pictograph that represents selected results from a surv

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	>=30000	<30000	total
no college	300	300	600
college	600	800	1400
total	900	1100	2000

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The above is a pictograph that represents selected results from a surv

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