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 →

Trignometry problem

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 645
Joined: Wed Sep 05, 2007 4:37 amFollowed by: 5 members
Location: India
Thanked: 34 times
by camitava » Fri Sep 14, 2007 4:41 am
Again a trignometric problem ...

18. The figure above represents a rectangular parking lot that is 30 meters by 40 meters and an attached semicircular driveway that has an outer radius of 20 meters and an inner radius of 10 meters. If the shaded region is not included, what is the area, in square meters, of the lot and driveway?
(A) 1,350π
(B) 1,200 + 400π
(C) 1,200 + 300π
(D) 1,200 + 200π
(E) 1,200 + 150π

To me, C is coming as the correct choice. But in the answer, it is saying that the OC is E. How and why, friends?
Attachments
clip_image002.gif
Correct me If I am wrong


Regards,

Amitava
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 105
Joined: Mon Sep 18, 2006 12:34 pm
Location: OH
Thanked: 7 times
GMAT Score:780

by mschling52 » Fri Sep 14, 2007 5:01 am
I agree with C.

Area of rectangle = 1200
Area of semicircle = 400(pi)
Area of shaded = 100(pi)

Total w/o shaded = 1200+400(pi)-100(pi) = 1200+300(pi)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 103
Joined: Wed May 30, 2007 6:17 amFollowed by: 1 member

by tanyajoseph » Fri Sep 14, 2007 5:23 am
Area of rect = 1200
Area of Outer CIRCLE - 400pi
Area of Inner CIRCLE - 100pi

So area of semicircle excluding inner circle should be either (400pi-100pi)/2
or 400pi/2 - 100pi/2 which would both give 150 pi.
So answer would be 1200 + 150 pi --->E

Key: The catch is to calculate the area of semicircle and not the area of circle
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 321
Joined: Tue Aug 28, 2007 5:42 am
Thanked: 1 times

by kajcha » Fri Sep 14, 2007 5:31 am
Should be E
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 645
Joined: Wed Sep 05, 2007 4:37 amFollowed by: 5 members
Location: India
Thanked: 34 times

by camitava » Sat Sep 15, 2007 12:07 am
Ohhhhh! Now got it. Thanks a lot friends. Look another example of overlook and carelessness. While solving the problem, I really forgot that we are dealing with semi-circles not a circle! Look how careless I am.
Correct me If I am wrong


Regards,

Amitava
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Senior | Next Rank: 100 Posts
Posts: 45
Joined: Wed Jun 20, 2007 12:40 pm
Location: Cleveland, OH

by niks_01.27 » Sun Sep 16, 2007 3:21 pm
I always write on the scratch paper things like "semi-circle" here, that helps. You can also try it out.
regards
niks...
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1