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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

A low-pressure weather system is approaching Plainville; [#permalink]

Show Tags

07 Mar 2006, 10:27

00:00

A

B

C

D

E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct
0% (00:00) wrong based on 2 sessions

HideShow timer Statistics

A low-pressure weather system is approaching Plainville; rainfall results from about 70 percent of such systems in the Plainville area. Moreover, the current season, spring, is the time of year in which thundershowers, which sometimes result from low-pressure systems, are most likely to occur in Plainville.
Knowing which one of the following, in addition to the information above, would be most useful for determining the probability that Plainville will have a thundershower soon?
(A) the percentage of thundershowers in Plainville that occur in the spring
(B) the percentage of spring rainfalls in Plainville that are thundershowers
(C) the percentage of thundershowers in Plainville that result from low-pressure systems
(D) whether low-pressure systems in other areas are associated with rainfall
(E) whether Plainville has more or fewer thundershowers each spring than do nearby towns

if: percentage of spring rainfalls in Plainville that are thundershowers = 90 %

p(thundershowers) = 0.70 * 0.90

if: percentage of spring rainfalls in Plainville that are thundershowers = 30% p(thundershowers) = 0.70 * 0.30

But can't I use the same arguement for C?

" thundershowers, which sometimes result from low-pressure systems"

What if the % of thundershowers from low pressure is .1 or .9?

Exactly my thoughts.
If percentage of thunderstorms from low pressure in Plainville is 70, then the probability of thunderstorm will be .7
B has 2 links to get the probability
C has direct link for the probability.
Still not sure if B is the correct choice.

B. I was torn b/w B and C. The reason I thought C was wrong was b/c the question asks, "Knowing which one of the following, in addition to the information above, would be most useful for determining the probability that Plainville will have a thundershower soon?" --- Meaning what's the probability there will be a thunderstorm in SPRING (soon). The answer choice that best helps us answer that question is the one which tells us the pct of spring rainfalls that lead to thunderstorms. We already know the pct of low pressure systems that lead to rainfall(70%).

Even though B is two steps away from the initial event (low pressure systems), it gives the best information. C could tell us the percentage of thunderstorms that occur from low pressure systems all year long, which is not as relevant as B. Just my 2 cents.