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

Redeem

Looks easy..but want to confirm answer

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 30
Joined: Sun Apr 27, 2008 4:22 pm

Looks easy..but want to confirm answer

by mav800rick » Thu May 29, 2008 3:23 pm
On an aerial photograph, the surface of a pond appears as circular region of radius 16/7 inch. If a distance of 1 inch on the photograph corresponds to an actual distance of 2 miles, which of the following is the closest estimate of the actual surface area of the pond, in square miles?

A. 1.3
B. 2.4
C. 3.0
D. 3.8
E. 5.0
Top
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 178
Joined: Wed May 14, 2008 3:51 pm
Thanked: 16 times
Followed by:1 members
GMAT Score:99%+

by egybs » Thu May 29, 2008 4:16 pm
I think you got the question wrong. With those numbers none of the answers make sense. Instead of 16/7 inches i think it should be 7/16 inches.... In which case the answer is 2.4.

7/16 inches * 2 miles/inch = 14/16 = 7/8.

Now:
Pi*( 7/8 )^2 = ~3*(49/64)= ~ 150/64 = ~75/32 or somewhere around 2.5, but we know it's less than 3 and greater than 2.

The only answer that fits is B... 2.4.
Top
User avatar
Legendary Member
Posts: 566
Joined: Fri Jan 04, 2008 11:01 am
Location: Philadelphia
Thanked: 31 times
GMAT Score:640

by AleksandrM » Fri May 30, 2008 9:07 am
mav,

With the numbers you posted I am getting 2.9, which is about 3.0. Let us know the OA.
Top
Master | Next Rank: 500 Posts
Posts: 178
Joined: Wed May 14, 2008 3:51 pm
Thanked: 16 times
Followed by:1 members
GMAT Score:99%+

by egybs » Fri May 30, 2008 9:17 am
Actually, if you use the numbers he posted you get ~60.

16/7 inches * 2 miles/inch = 32/7 miles

The surface area in square miles will be: pi(32/7)^2

which is pi(1024/49) or about 3000/50 = ~60

If you use a calculator and a few digits of pi, you get around 65.6.

AleksandrM wrote:mav,

With the numbers you posted I am getting 2.9, which is about 3.0. Let us know the OA.
Top
Master | Next Rank: 500 Posts
Posts: 192
Joined: Tue Apr 29, 2008 7:41 am
Thanked: 14 times

by aatech » Fri May 30, 2008 9:20 am
1 inch = 2 miles

16/7 inch = 32/7 miles

area = pi*32/7*32/7 = 65.67

Are you sure the question is correct?
Top
Senior | Next Rank: 100 Posts
Posts: 30
Joined: Sun Apr 27, 2008 4:22 pm

OA...is 2.4

by mav800rick » Fri May 30, 2008 2:34 pm
one needs to convert inches to miles and then square it. we get 2.4 approx with that.

and its 7/16 and not 16/7.
Top
User avatar
Newbie | Next Rank: 10 Posts
Posts: 1
Joined: Mon Aug 01, 2011 11:04 am

by maggi » Mon Aug 01, 2011 11:05 am
hey everyone !!!
isn't the surface area be ( 2 pie r ) which is equal to approx 5 : answer choice (e)
Top
Master | Next Rank: 500 Posts
Posts: 370
Joined: Sat Jun 11, 2011 8:50 pm
Location: Arlington, MA.
Thanked: 27 times
Followed by:2 members

by winniethepooh » Mon Aug 01, 2011 11:46 am
Wrong question, don't try to solve!
You never get the answer anywhere near the options.
Top
Post new topic Post Reply
• Page 1 of 1