At a charity event, 80 volunteers were assigned to exactly one of two

Question

At a charity event, 80 volunteers were assigned to exactly one of two roles: setup crew or check-in desk. If one volunteer is selected at random from the 80 volunteers, is the probability greater than 3/10 that the selected volunteer is a woman on the setup crew?

(1) There were 45 men among the 80 volunteers.

(2) There were 22 volunteers on the setup crew.

M47-201

Bunuel · Accepted Answer

GMAT Club Official Solution:

At a charity event, 80 volunteers were assigned to exactly one of two roles: setup crew or check-in desk. If one volunteer is selected at random from the 80 volunteers, is the probability greater than 3/10 that the selected volunteer is a woman on the setup crew?

The question asks:

Is {women on setup crew}/80 > 3/10?

Is {women on setup crew} > 24?

Thus, the question is equivalent to asking whether there were more than 24 women on the setup crew.

(1) There were 45 men among the 80 volunteers.

So there were:

80 - 45 = 35 women

But we do not know how many of these women were on the setup crew. The number of women on the setup crew could be more than 24 or not more than 24.

Not sufficient.

(2) There were 22 volunteers on the setup crew.

Since there were only 22 volunteers on the setup crew in total, the number of women on the setup crew could not possibly be more than 22. So the number of women on the setup crew was definitely not more than 24. The answer to the question is NO.

Sufficient.

Answer: B.

vasu1104 · Answer

total 80.
two roles : setup crew or check in

we have men and woman.
and each is assigned exactly one role.

m 
 w 
 total 
 
  SC 
  
 p

CD

total

80

find p/80 > 3/10
p> 24

essentially we need to find woman in SC> 24 or not?

S-1
m - 45, w- 35.
but we don't know anything about num of people in SC and CD.
not sufficient.

S-2
total SC -22
total CD = 58

that means max woman in SC can be 22. not more than 22.
if not more than 22 then more than 24 as well.

sufficient

option B

GulfTube · Answer

is probability that the selected volunteer is a woman on the setup crew greater than 3/10 ?
since there are total 80 volunteers, total possible outcomes is 80, hence 10 is scaled down by factor of 8. 3*8 = 24. 
 Question re-phrased: is number of selected volunteer women on the setup crew greater than 24?

i) Men = 45, so total women = 80-45 = 35. Women on setup crew could be 25 out of these 35 which would be >24, but could also be 1 out of these 35 which would be <24.  not sufficient.

ii) total volunteers on setup crew = 22. since women on setup crew are a subset of total volunteers on setup crew , this means the women on setup crew are definitively less than 24. sufficient.

Answer B

At a charity event, 80 volunteers were assigned to exactly one of two

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GMAT Data Sufficiency (DS) Questions

At a charity event, 80 volunteers were assigned to exactly one of two

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

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