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 →

circular gears

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 69
Joined: Fri Jun 19, 2009 11:46 am
Location: London
Thanked: 1 times
by LevelOne » Fri Jul 03, 2009 1:06 pm
1) Circular gears P and Q start rotating at the same time at constant speeds. Gear P makes 10 revolutions per minute, and gear Q makes 40 revolutions per minute. How many seconds after the gears start rotating will gear Q have made exactly 6 more revolutions than gear P?

A. 6
B. 8
C. 10
D. 12
E. 15

2) The value of 10^8 - 10^2/10^7 - 10^3 is closest to which of the following?

A. 1
B. 10
C. 10^2
D. 10^3
E. 10^4

thanks
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
Legendary Member
Posts: 1161
Joined: Mon May 12, 2008 2:52 amFollowed by: 1 member
Location: Sydney
Thanked: 23 times

by mehravikas » Fri Jul 03, 2009 8:21 pm
Answer to Question 1 -

P = 10 rev per minute -> in one second it makes 10/60 = 1/6 rev per sec
Q = 40 rev per min -> in 1 sec = 40/60 = 2/3 rev per sec

1/6 * t + 6 = 2/3 * t

solve for t and you'll get 12. Answer D
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 69
Joined: Fri Jun 19, 2009 11:46 am
Location: London
Thanked: 1 times

by LevelOne » Fri Jul 03, 2009 10:37 pm
OA is D. how about exponents in (2)?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 575
Joined: Tue Nov 04, 2008 2:58 amFollowed by: 4 members
Location: India
Thanked: 18 times
GMAT Score:710

by rahulg83 » Sat Jul 04, 2009 5:19 am
2) The value of 10^8 - 10^2/10^7 - 10^3 is closest to which of the following?

A. 1
B. 10
C. 10^2
D. 10^3
E. 10^4
i suppose question asks for value of (10^8 - 10^2)/(10^7 - 10^3), it can be written as 10^2{(10^6)-1}/10^3{(10^4)-1}, now 1 can be neglected in comparison with 10^6 or 10^4

So our expression will now reduce to (10^2*10^6)/(10^3*10^4)=10 ans..
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 69
Joined: Fri Jun 19, 2009 11:46 am
Location: London
Thanked: 1 times

by LevelOne » Sat Jul 04, 2009 5:31 am
rahulg83, thanks again.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 1161
Joined: Mon May 12, 2008 2:52 amFollowed by: 1 member
Location: Sydney
Thanked: 23 times

by mehravikas » Sun Jul 05, 2009 1:45 pm
Rahul,

can you explain how can you neglect 1 please?

Thanks,
Vikas
rahulg83 wrote:
2) The value of 10^8 - 10^2/10^7 - 10^3 is closest to which of the following?

A. 1
B. 10
C. 10^2
D. 10^3
E. 10^4
i suppose question asks for value of (10^8 - 10^2)/(10^7 - 10^3), it can be written as 10^2{(10^6)-1}/10^3{(10^4)-1}, now 1 can be neglected in comparison with 10^6 or 10^4

So our expression will now reduce to (10^2*10^6)/(10^3*10^4)=10 ans..
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 24
Joined: Mon May 19, 2008 3:48 pm

by kath_the_great4 » Sun Jul 05, 2009 7:15 pm
1 is insignificant when you are dealing with numbers in the thousands...we are not looking for an exact response here.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1