Last visit was: 22 Dec 2024, 18:29 It is currently 22 Dec 2024, 18:29

Close

GRE Prep Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GRE score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel
avatar
Intern
Intern
Joined: 30 Apr 2016
Posts: 12
Own Kudos [?]: 17 [0]
Given Kudos: 0
Send PM
Verbal Expert
Joined: 18 Apr 2015
Posts: 30475
Own Kudos [?]: 36821 [0]
Given Kudos: 26100
Send PM
User avatar
Retired Moderator
Joined: 07 Jun 2014
Posts: 4815
Own Kudos [?]: 11268 [1]
Given Kudos: 0
GRE 1: Q167 V156
WE:Business Development (Energy and Utilities)
Send PM
avatar
Intern
Intern
Joined: 22 Oct 2016
Posts: 15
Own Kudos [?]: 7 [0]
Given Kudos: 0
Send PM
Thirty airmail and 40 ordinary envelopes are the only envelo [#permalink]
Thirty airmail and 40 ordinary envelopes are the only envelopes in a bag. Thirty-five envelopes in the bag are unstamped, and 5/7 of the unstamped envelopes are airmail letters. What is the probability that an envelope picked randomly from the bag is an unstamped airmail envelope?

(A) 1/7
(B) 1/3
(C) 13/35
(D) 17/38
(E) 23/70

25 which is 5/7 of 35 unstamped airmail envelopes.

so , P(unstamped airmail) = 25/70 => 5/14 is not in the options .
am i missing anything?

Originally posted by ssiva on 25 Nov 2016, 02:54.
Last edited by Carcass on 05 Dec 2016, 02:36, edited 1 time in total.
Edited the post
User avatar
Retired Moderator
Joined: 07 Jun 2014
Posts: 4815
Own Kudos [?]: 11268 [0]
Given Kudos: 0
GRE 1: Q167 V156
WE:Business Development (Energy and Utilities)
Send PM
Re: my answer was not in the answer [#permalink]
Expert Reply
I think you are right. Unstamped ordinary is 10/70 or 1/7. Probably a typo.
Verbal Expert
Joined: 18 Apr 2015
Posts: 30475
Own Kudos [?]: 36821 [0]
Given Kudos: 26100
Send PM
Re: Thirty airmail and 40 ordinary envelopes are the only envelo [#permalink]
Expert Reply
Please follow the rules for posting in quant section. They are as announcement in main quant section

Thank you for your collaboration
avatar
Intern
Intern
Joined: 15 Dec 2016
Posts: 17
Own Kudos [?]: 14 [0]
Given Kudos: 0
Send PM
Re: Thirty airmail and 40 ordinary envelopes are the only envelo [#permalink]
Yes, none of the answers are correct. Unstamped aitmail letters are 25 letters out of 70, so the answer should be 25/70 or 5/14.
Verbal Expert
Joined: 18 Apr 2015
Posts: 30475
Own Kudos [?]: 36821 [0]
Given Kudos: 26100
Send PM
Re: Thirty airmail and 40 ordinary envelops [#permalink]
Expert Reply
Merged similar topic. The OA is A.

Quote:
We have that 30 airmail and 40 ordinary envelopes are the only envelopes in the bag. Hence, the total number of envelopes is 30 + 40 = 70. We also have that 35 envelopes in the bag are unstamped, and 5/7 of these envelopes are airmail letters. Now, 5/7 * 35 = 25. So the remaining 35 – 25 = 10 are ordinary unstamped envelopes. Hence, the probability of picking such an envelope from the bag is
(Number of unstamped ordinary envelopes) / (Total number of envelopes) =10/70 =1/7
Target Test Prep Representative
Joined: 09 May 2016
Status:Head GRE Instructor
Affiliations: Target Test Prep
Posts: 183
Own Kudos [?]: 276 [0]
Given Kudos: 114
Location: United States
Send PM
Re: Thirty airmail and 40 ordinary envelops [#permalink]
1
Expert Reply
happy1992 wrote:
Thirty airmail and 40 ordinary envelops are the only envelop in a bag. Thirty-five envelops in the bag are unstamped, and \(\frac{5}{7}\) of the unstamped envelops are airmail. What is the probability that an envelope picked randomly from the bag is an unstamped airmail envelope?

(A) \(\frac{1}{7}\)

(B) \(\frac{1}{3}\)

(C) \(\frac{13}{35}\)

(D) \(\frac{17}{38}\)

(E) \(\frac{23}{70}\)



We have 30 airmail and 40 originary envelopes for a total of 70 envelopes.

Since 5/7 of the 35 unstamped envelopes are airmail, 5/7 x 35 = 25 envelopes are unstamped airmail.

So the probability of selecting an unstamped airmail envelope is 25/70 = 5/14 (not in the answer choices)
avatar
Intern
Intern
Joined: 01 May 2018
Posts: 19
Own Kudos [?]: 0 [0]
Given Kudos: 0
Send PM
Re: Thirty airmail and 40 ordinary envelops [#permalink]
it looks very complicated question
User avatar
Director
Director
Joined: 22 Jun 2019
Posts: 521
Own Kudos [?]: 722 [0]
Given Kudos: 161
Send PM
Thirty airmail and 40 ordinary envelopes are the only envelo [#permalink]
Thirty airmail and 40 ordinary envelopes are the only envelopes in a bag. Thirty-five envelopes in the bag are unstamped, and \(\frac{5}{7}\) of the unstamped envelopes are airmail letters. What is the probability that an envelope picked randomly from the bag is an ordinary airmail envelope?

(A) \(\frac{1}{7}\)

(B) \(\frac{1}{3}\)

(C) \(\frac{5}{14}\)

(D) \(\frac{17}{38}\)

(E) \(\frac{23}{70}\)
User avatar
Director
Director
Joined: 22 Jun 2019
Posts: 521
Own Kudos [?]: 722 [0]
Given Kudos: 161
Send PM
Re: Thirty airmail and 40 ordinary envelopes are the only envelo [#permalink]
Need explanation.
avatar
Intern
Intern
Joined: 19 Nov 2019
Posts: 3
Own Kudos [?]: 0 [0]
Given Kudos: 0
Send PM
Re: Thirty airmail and 40 ordinary envelopes are the only envelo [#permalink]
huda wrote:
Thirty airmail and 40 ordinary envelopes are the only envelopes in a bag. Thirty-five envelopes in the bag are unstamped, and \(\frac{5}{7}\) of the unstamped envelopes are airmail letters. What is the probability that an envelope picked randomly from the bag is an ordinary airmail envelope?

(A) \(\frac{1}{7}\)

(B) \(\frac{1}{3}\)

(C) \(\frac{5}{14}\)

(D) \(\frac{17}{38}\)

(E) \(\frac{23}{70}\)

Need explation, because I got 3/7 ans
Verbal Expert
Joined: 18 Apr 2015
Posts: 30475
Own Kudos [?]: 36821 [0]
Given Kudos: 26100
Send PM
Re: Thirty airmail and 40 ordinary envelops [#permalink]
Expert Reply
Merged similar topic. See the explanations above and use the search tool https://gre.myprepclub.com/forum/search.php before to post a new question.

Regards
User avatar
Director
Director
Joined: 22 Jun 2019
Posts: 521
Own Kudos [?]: 722 [0]
Given Kudos: 161
Send PM
Re: Thirty airmail and 40 ordinary envelops [#permalink]
Carcass wrote:
Merged similar topic. See the explanations above and use the search tool https://gre.myprepclub.com/forum/search.php before to post a new question.

Regards


Sorry do not understand. And please mention the one whom you to write.
Prep Club for GRE Bot
Re: Thirty airmail and 40 ordinary envelops [#permalink]
Moderators:
Retired Moderator
6218 posts
Moderator
1115 posts
Retired Moderator
187 posts
Retired Moderator
348 posts
Retired Moderator
160 posts
GRE Instructor
117 posts
Retired Moderator
63 posts
Retired Moderator
1307 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne