Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 58464

On a certain airline, customers are assigned a row number when they pu
[#permalink]
Show Tags
06 Mar 2017, 03:56
Question Stats:
58% (01:44) correct 42% (01:47) wrong based on 123 sessions
HideShow timer Statistics
On a certain airline, customers are assigned a row number when they purchase their ticket, but the four seats within the row are first come, first served during boarding. If Karen and Georgia end up with random seats in the same row on a soldout flight, what is the probability that they sit next to each other? A. 25% B. 40% C. 50% D. 75% E. 80%
Official Answer and Stats are available only to registered users. Register/ Login.
_________________



Intern
Joined: 09 Sep 2016
Posts: 35
Location: Georgia
Concentration: Finance, International Business
GPA: 3.75
WE: Analyst (Investment Banking)

Re: On a certain airline, customers are assigned a row number when they pu
[#permalink]
Show Tags
06 Mar 2017, 07:03
i dont know if i am correct but here how i would do it: probability of karen sitting on the edge of the row is 2/4 = 1/2 , if karen sits on the edge there is one possibility for georgia to sit besides her so probability would be 1/3 for here. together 1/2*1/3=1/6 the probability of karen sitting mid is 1/2 and probability of georgia sitting besides her is 2/3  so together 1/2*2/3=2/6
together 1/6 + 2/6 = 3/6 = 50%



Chat Moderator
Joined: 07 Mar 2016
Posts: 49

On a certain airline, customers are assigned a row number when they pu
[#permalink]
Show Tags
Updated on: 06 Mar 2017, 08:54
Easiest way to solve, for myself atleast, is to illustrate: let "x" be the customers and "o" be the open seats xxoo oxxo ooxx xoxo oxox xoox 3 ways that the pair can sit together out of a total of 6 arrangements. Simply divide and the result is 50%.
_________________
...once in a while you get shown the light, in the strangest of places if you look at it right...
Originally posted by emockus on 06 Mar 2017, 07:35.
Last edited by emockus on 06 Mar 2017, 08:54, edited 2 times in total.



Intern
Joined: 26 Feb 2017
Posts: 3

Re: On a certain airline, customers are assigned a row number when they pu
[#permalink]
Show Tags
06 Mar 2017, 08:22
There is 4C2 ways Karen and Georgia can sit in the row. There is 3C1 ways Karen and Georgia can sit togheter in the row (Imagine Karen and Georgia as a single unit, so there are just 3 other seats to ocuppy).
(Farovable outcomes)/(total outcomes) = 3C1/4C2 = 3/6 = 50%



Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8137
Location: United States (CA)

Re: On a certain airline, customers are assigned a row number when they pu
[#permalink]
Show Tags
07 Mar 2017, 17:19
Bunuel wrote: On a certain airline, customers are assigned a row number when they purchase their ticket, but the four seats within the row are first come, first served during boarding. If Karen and Georgia end up with random seats in the same row on a soldout flight, what is the probability that they sit next to each other?
A. 25% B. 40% C. 50% D. 75% E. 80% In a row of 4 seats, there are 4! = 24 sitting arrangements for 4 people. Now let’s find the number of ways that Karen (K) and Georgia (G) will be sitting next to each other. Let’s designate the other two passengers as A and B, and they are sitting in the same row as Karen and Georgia. The arrangement could be as follows: [KG][A][B] Since K and G are sitting next to each other, we can count [KG] as one person, such that there are 3 people sitting in the same row, and thus the number of ways to arrange those 3 people is 3! = 6. However, since we can arrange KG in 2! ways (KG or GK), the number of ways to arrange the “3 people” is actually 2 x 6 = 12. Thus, the probability that Karen and Georgia are sitting next to each other is 12/24 = 1/2 = 50%. Answer: C
_________________
5star rated online GMAT quant self study course See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews If you find one of my posts helpful, please take a moment to click on the "Kudos" button.



Intern
Joined: 16 Jan 2017
Posts: 5

Re: On a certain airline, customers are assigned a row number when they pu
[#permalink]
Show Tags
10 Mar 2017, 04:50
How can there be 12 different ways that they sit next to each other? I even drew it out and still dont get it.
1 / 2 / 3 / 4 k / g / x /x g/ k / x /x x / k / g / x x/ g / k / x x / x / k / g x / x / g / k
for me there would be 6 different ways. out of 24 possible arrangements. therefore I would say answer A.
Please tell me where my mistake lies.



Intern
Joined: 15 Sep 2015
Posts: 16

Re: On a certain airline, customers are assigned a row number when they pu
[#permalink]
Show Tags
10 Mar 2017, 09:27
Consider K & G to be one group as they will be sitting next to each other. Therefore, the total arrangements among 3 seats (K&G is one & other two) will be 3!x2!, since within the group, K & G can sit in two ways. Divide by total no of possibilities  4!. Therefore ans is 50%



Director
Joined: 27 May 2012
Posts: 904

On a certain airline, customers are assigned a row number when they pu
[#permalink]
Show Tags
20 Mar 2018, 06:46
Bunuel wrote: On a certain airline, customers are assigned a row number when they purchase their ticket, but the four seats within the row are first come, first served during boarding. If Karen and Georgia end up with random seats in the same row on a soldout flight, what is the probability that they sit next to each other?
A. 25% B. 40% C. 50% D. 75% E. 80% Consider KG as one unit hence A{KG}B where A and B are the other two passengers hence total ways to arrange them is \(3_C_1\) = 3 A and B can be arranged in \(2_C_ {1}\) =2 ways KG themselves can be arranged in \(2_C_{1}\) =2 ways Hence total favorable cases that they can be arranged in are 3*2*2 =12 Total arrangements are 4*3*2*1 =24 hence probability = \(\frac{12}{24}\) = 50%
_________________



Intern
Joined: 03 Jun 2019
Posts: 22

Re: On a certain airline, customers are assigned a row number when they pu
[#permalink]
Show Tags
29 Jun 2019, 08:18
Bunuel wrote: On a certain airline, customers are assigned a row number when they purchase their ticket, but the four seats within the row are first come, first served during boarding. If Karen and Georgia end up with random seats in the same row on a soldout flight, what is the probability that they sit next to each other?
A. 25% B. 40% C. 50% D. 75% E. 80% Can anyone please help in understanding the problem which i had some difficulties with. The problem says 4 random seats are on first come first serve basis in a row, it is only mentioned that K & G end up in same row and not said that in the same 4 random seats assigned on FCFS basis. So isn't there any probability for them to end up in seats other than the 4 seats. So they may come first and sits next in that 4 seats and may come and six next to one other in the remaining seats. This thought really caught me, can any please help me get out of this please.



Director
Joined: 27 May 2012
Posts: 904

On a certain airline, customers are assigned a row number when they pu
[#permalink]
Show Tags
29 Jun 2019, 09:10
Sreeragc wrote: Bunuel wrote: On a certain airline, customers are assigned a row number when they purchase their ticket, but the four seats within the row are first come, first served during boarding. If Karen and Georgia end up with random seats in the same row on a soldout flight, what is the probability that they sit next to each other?
A. 25% B. 40% C. 50% D. 75% E. 80% Can anyone please help in understanding the problem which i had some difficulties with. The problem says 4 random seats are on first come first serve basis in a row, it is only mentioned that K & G end up in same row and not said that in the same 4 random seats assigned on FCFS basis. So isn't there any probability for them to end up in seats other than the 4 seats. So they may come first and sits next in that 4 seats and may come and six next to one other in the remaining seats. This thought really caught me, can any please help me get out of this please. Hi Sreeragc, Thank you for sharing your query: May be this will help Passengers are only assigned row numbers they are not assigned seat numbers. K and G receive the same row number, hence they will be in the same row, doesn't matter which row they will be in, question is asking probability of them sitting next to each other, it's already given they will be in the same row. Question is not asking , find probability of them sitting in the same row and then sit next to each other. It's already given they are given the same row number.Don't think of choosing a row from various rows, that is not being asked. Let me know if anything is still unclear.
_________________



Intern
Joined: 03 Jun 2019
Posts: 22

Re: On a certain airline, customers are assigned a row number when they pu
[#permalink]
Show Tags
29 Jun 2019, 10:56
stne wrote: Sreeragc wrote: Bunuel wrote: On a certain airline, customers are assigned a row number when they purchase their ticket, but the four seats within the row are first come, first served during boarding. If Karen and Georgia end up with random seats in the same row on a soldout flight, what is the probability that they sit next to each other?
A. 25% B. 40% C. 50% D. 75% E. 80% Can anyone please help in understanding the problem which i had some difficulties with. The problem says 4 random seats are on first come first serve basis in a row, it is only mentioned that K & G end up in same row and not said that in the same 4 random seats assigned on FCFS basis. So isn't there any probability for them to end up in seats other than the 4 seats. So they may come first and sits next in that 4 seats and may come and six next to one other in the remaining seats. This thought really caught me, can any please help me get out of this please. Hi Sreeragc, Thank you for sharing your query: May be this will help Passengers are only assigned row numbers they are not assigned seat numbers. K and G receive the same row number, hence they will be in the same row, doesn't matter which row they will be in, question is asking probability of them sitting next to each other, it's already given they will be in the same row. Question is not asking , find probability of them sitting in the same row and then sit next to each other. It's already given they are given the same row number.Don't think of choosing a row from various rows, that is not being asked. Let me know if anything is still unclear. Thank you stne, that was a great help, four seats within the row was the real point i was missing. Now i got it, each row only has four sets. Now its good to go with the rest. Thanks again.




Re: On a certain airline, customers are assigned a row number when they pu
[#permalink]
29 Jun 2019, 10:56






