Of the 700 members of a certain organization, 120 are lawyers. Two mem

Question

Of the 700 members of a certain organization, 120 are lawyers. Two members of the organization will be selected at random. Which of the following is closest to the probability that neither of the members selected will be a lawyer?

A. 0.5
B. 0.6
C. 0.7
D. 0.8
E. 0.9

A. 0.5
B. 0.6
C. 0.7
D. 0.8
E. 0.9

chetan2u · Accepted Answer

Hi..
this is not the correct way..
1-P( both are lawyers) = P that both are not lawyer, so it will include when 1 of them is a lawyer... so wrong

here we are looking for NEITHER is a lawyer, so both are NOT lawyer, so 580C2
P =  \frac{580}{700}*\frac{579}{699} ~ (\frac{580}{700})^2=(\frac{560+20}{700})^2=(0.8+0.03)^2=0.83^2=  something more than 0.65 so answer 0.7
C

sunita123 · Answer

Probability of selecting 2 lawyers

120/700* 120*700 =0.2(approx)

Now probability of neither of the members is a lawyer = 1- 0.2= 0.8 (approx)

Ans: D

PKN · Answer

P(neither lawyer)= \frac{Ways-of-selecting-both-non-Lawyers}{Ways-of-selecting-2-members-out--of-700-members} 
 = \frac{580C2}{700C2} 
 =0.68
0.68 can be approximated to 0.7.

Ans. (C)

KSBGC · Answer

Note : we are asked to determine the probability of members who are not lawyer.

Total case : 700C2

Probable event = (700 - 120 ) = 580C2

Probability = 580C2 / 700C2

= 0.68 ~ 0.7.

The best answer is C.

GyMrAT · Answer

# of non lawyers = 700 - 120 = 580

Probability of selecting 2 non lawyers = (580/700)*(579/699) =~ (580/700)*(580/700) =0.6889 =~0.7

Answer C.

Thanks,
GyM

ScottTargetTestPrep · Answer

Since 580 are not lawyers, the probability of selecting two members, neither of whom are lawyers, is:

580/700 x 579/699

Notice that the second fraction is approximately 580/700, so we can approximate the probability as:

580/700 x 580/700 = 58/70 x 58/70 = 29/35 x 29/35 ≈ 30/35 x 30/35 = 6/7 x 6/7 = 36/49 ≈ 36/50 = 0.72 
Of the numbers in the given choices, the closest to this is 0.7.

Answer: C

tatz · Answer

tatz · Answer

Sir, Can you please help me in removing my concept gap. I tried to solve it in a very layman way. * Select one person from 580 and second person from 579 =(1/580) x (1/579)

Izzyjolly · Answer

This is not correct way to solve this question.
Since you mention "select one person from 580 ...", you can think it this way:

ways of selecting 1st member from 580 members who are not lawyers = 580C1 = 580
ways of selecting 2nd member from 579 members who are not lawyers = 579C1 = 579
Total possible ways = 700 (ways of selecting 1st member from 700 members) * 699 (ways of selecting 2nd member from the rest 699 members)

Therefore, Probability of selecting both members who are not lawyer = (580*579) / (700*699) = 0.7 (approx.)
Answer: C.

Hope it helps.

tatz · Answer

Thanks Izzyjust5.. it made things clear .. 
Probably selecting 1 object out of 580 objects (1/580) will be correct only when all objects are same/similar like all are red balls or green pens. 
In case all objects are unique, we need to use combinations.. "r objects can be selected from a set of n unique objects in nCr ways.."

Abhishek009 · Answer

L = 120 ; L' = 580

Required Probability will be 580/700*579/699 ~ 0.70, Answer must be (C)

Crytiocanalyst · Answer

579*580 / 700*699 approx = 600*600 / 700*700

=> 36/49 = 0.7

Therefore IMO C

bumpbot · Answer

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Of the 700 members of a certain organization, 120 are lawyers. Two mem

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