Jill has applied for a job with each of two different companies. What

When you subtract probability of neither from 1, you will get probability of offer from at least 1 coy.
So this probability will include - p of only say A company, p of only B and p of both A and B.
Whereas we are looking for the value of probability of both A and B.

Oops ... My bad .. yes the correct answer is C
I see I made a mistake in interpreting statement B in conjunction with the stimulus

The answer is indeed C
Thanks for pointing out the error.

This question can be easily solved using the double matrix method:

Hi experts,

chetan2u, MathRevolution, ScottTargetTestPrep, abhimahna, AaronPond, BrentGMATPrepNow, GMATBusters

Sorry for tagging everyone. Cunning I am I know (1 reply will suffice). I just want to confirm my understanding of the approach after going through the forum.
 

Let the probability of getting the job 1st company be A.
Let the probability of getting the job only from company A be 'a'.
Let the probability of getting the job from the 2nd company be B.
Let the probability of getting the job only from company B be 'b'.
Let the probability of getting the job from both the companies be 'c'.
Let the probability of getting the job from neither company be 'n'.
A = a + c
B = b + c
Find P(A&B) =?
P(A or B) = P(A) + P(B) - P(A&B) =P (a + c) + P(b + c) - P(c) = P(a) + P(b) + P(c)

Statement 1. P(n) = 0.3

P(a) + P(b) + P(c) + 0.3 = 1
P(a) + P(b) + P(c) = 0.7 Not sufficient

Statement 2. P (a) + P(b) = 0.5

P(A or B) = P(a) + P(b) + P(c)

P(A or B) = 0.5 + P(c) Not sufficient

Combining both the statements
0.7 = 0.5 + P(c)
P(c) = 0.2 Therefore, sufficient.

Takeaway: P(event 1 or event 2) = P(event 1) + P(event 2) - P(event 1 & event 2) So this formula basically stems from the Venn diagram consisting of 2 circles. Am I correct?

Thank you.

Hate to add to the thread but I must ask - Why can't I utilize the formula 1-(percent of neither)=(percent of both)? I took this approach and landed on A which cleary wasn't correct. Can someone please help?

Yes, you are correct in the approach.

P(Total) = 1 = P(no offer) + P(Exactly one offer) + P(two offers)
Option 1 implies 0.3 + P(Exactly one offer) + P(two offers) = 1 . INSUFFICIENT
Option 2 implies P(no offer) + 0.5 + P(two offers) = 1. INSUFFICIENT
Together implies 0.3 + 0.5 + P(two offers) = 1 . SUFFICIENT

I am also struggling with the wording on this one.

Considering this equation: Pb = 1−Ps−Pt−Pn , in my opinion "exactly one" can mean one of two things:

I) Ps or Pt
She can get an offer from S or T, therefore leading to E, neither statement is sufficient.

II) Ps + Pt
Obviously leading to C.

So, how can we be sure to what the question is referring to?

Cheers

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