BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

DS Probability

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 22
Joined: Tue Mar 27, 2007 6:30 am
by Bhandaripreeti » Mon Oct 15, 2007 5:05 am
What is the chance that Martha wins the first 5 rounds and loses the sixth?



(1) The chance that Martha wins the first 4 rounds and loses the fifth is 1/32



(2) The chance that Martha wins the first 6 rounds and loses the seventh is 1/128 .


Hi,

I thought the answer is D considering the numerator is 1 so the probability would be 1/2 however the OA is E .
Source - Princeton
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |
Senior | Next Rank: 100 Posts
Posts: 50
Joined: Thu Oct 04, 2007 12:26 pmFollowed by: 3 members
Location: RTP, NC
Thanked: 26 times

by achandwa » Mon Oct 15, 2007 7:05 am
Let P(w1), P(w2), P(w3), P(w4), P(w5), P(w6), P(w7) denote the probably that Martha wins 1st, 2nd, 3rd, 4th, 5th, 6th, and 7th round respectively.
Let P(l1), P(l2), P(l3), P(l4), P(l5), P(l6), P(l7) denote the probably that Martha loses 1st, 2nd, 3rd, 4th, 5th, 6th, and 7th round respectively.

Probability that Martha wins the first 5 rounds and loses sixth = P(w1).P(w2).P(w3).P(w4).P(w5).P(l6)

(1) The chance that Martha wins the first 4 rounds and loses the fifth is 1/32
This provides you P(w1).P(w2).P(w3).P(w4).P(l5) - Insufficient to calculate the product above.

(2) The chance that Martha wins the first 6 rounds and loses the seventh is 1/128 .
This provides you P(w1).P(w2).P(w3).P(w4).P(w5).P(w6).P(l7) - Insufficient to calculate the product above.

Even taken together (1) and (2) are insufficient to calculate the produce P(w1).P(w2).P(w3).P(w4).P(w5).P(l6) - (E)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1