GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 23 Oct 2019, 19:56

Close

GMAT 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 GMAT 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

If the raining season in Jerusalem begins, Dora estimates a 20% probab

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
GMATH Teacher
User avatar
P
Status: GMATH founder
Joined: 12 Oct 2010
Posts: 935
If the raining season in Jerusalem begins, Dora estimates a 20% probab  [#permalink]

Show Tags

New post 08 Mar 2019, 07:46
1
1
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

56% (02:30) correct 44% (02:21) wrong based on 25 sessions

HideShow timer Statistics

GMATH practice exercise (Quant Class 19)

If the raining season in Jerusalem begins, Dora estimates a 20% probability of traveling to Israel next holidays. If it doesn´t, she guesses her probability of taking this trip is 250% higher. Based on these assumptions, what are Dora´s chances of traveling to Israel next holidays, if she knows there is a 70% probability for the raining season in Jerusalem to begin?

(A) 15%
(B) 29%
(C) 35%
(D) 42%
(E) 46%

_________________
Fabio Skilnik :: GMATH method creator (Math for the GMAT)
Our high-level "quant" preparation starts here: https://gmath.net
Intern
Intern
avatar
B
Joined: 25 Dec 2018
Posts: 2
If the raining season in Jerusalem begins, Dora estimates a 20% probab  [#permalink]

Show Tags

New post 08 Mar 2019, 09:49
2
There are two possibilities of Dora travelling
1. If it rains and she travels- p(rains) x p(travel)= 0.7 x 0.2 = 0.14
2. If it does not rain and she travels - p (doesn't rain) x p (travels when it doesn't rain)
Now, the question says that probability of travelling when it does not rain is higher by 250% means that, 250% of 20% = 0.5
therefore, probability of travelling when it doesn't rain is 0.2+0.5= 0.7
So, p (doesn't rain) x p (travels when it doesn't rain)= 0.3 (given in question) x 0.7 = 0.21
P (dora travels) = P (rains and travels) OR P (doesn't rain and travels)
= 0.14 + 0.21 = 0.35
Hope this is correct.
GMATH Teacher
User avatar
P
Status: GMATH founder
Joined: 12 Oct 2010
Posts: 935
Re: If the raining season in Jerusalem begins, Dora estimates a 20% probab  [#permalink]

Show Tags

New post 08 Mar 2019, 11:05
fskilnik wrote:
GMATH practice exercise (Quant Class 19)

If the raining season in Jerusalem begins, Dora estimates a 20% probability of traveling to Israel next holidays. If it doesn´t, she guesses her probability of taking this trip is 250% higher. Based on these assumptions, what are Dora´s chances of traveling to Israel next holidays, if she knows there is a 70% probability for the raining season in Jerusalem to begin?

(A) 15%
(B) 29%
(C) 35%
(D) 42%
(E) 46%
Yes, ss13ny , your solution is correct! Thanks for joining!

The official solution follows:

\(? = P\left( {{\rm{Dora}}\,\,{\rm{travels}}} \right)\)

\(P\left( {{\text{season}}\,\,{\text{raining}}} \right) = 70\% \,\,\,\,\,\, \Rightarrow \,\,\,\,\,P\left( {{\text{not}}\,\,{\text{season}}\,\,{\text{raining}}} \right) = 30\%\)

\(20\% \,\,\mathop \to \limits^{\, + \,250\% } \,\,\,\underbrace {60\% + 10\% }_{300\% \,\left( {20\% } \right)\, + \,50\% \left( {20\% } \right)} = 70\% \,\,\,\,\,\, \Rightarrow \,\,\,\,\,\left\{ \matrix{
P\left( {{\rm{travel}}\,\,{\rm{when}}\,\,{\rm{season}}\,\,{\rm{raining}}} \right) = 20\% \hfill \cr
P\left( {{\rm{travel}}\,\,{\rm{when}}\,\,{\rm{not \,\,season}}\,\,{\rm{raining}}} \right) = 70\% \hfill \cr} \right.\,\,\)


\(?\,\, = \,\,70\% \cdot 20\% + 30\% \cdot 70\% \,\, = \,\,\underleftrightarrow {70\% \cdot \left( {20\% + 30\% } \right)}\,\, = \,\,\frac{1}{2}\left( {70\% } \right)\,\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,\,\left( {\text{C}} \right)\)


We follow the notations and rationale taught in the GMATH method.

Regards,
Fabio.
_________________
Fabio Skilnik :: GMATH method creator (Math for the GMAT)
Our high-level "quant" preparation starts here: https://gmath.net
GMAT Club Bot
Re: If the raining season in Jerusalem begins, Dora estimates a 20% probab   [#permalink] 08 Mar 2019, 11:05
Display posts from previous: Sort by

If the raining season in Jerusalem begins, Dora estimates a 20% probab

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





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