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 →

Help: average problem

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 63
Joined: Sat Jul 24, 2010 10:29 amFollowed by: 1 member
Thanked: 1 times
GMAT Score:640
by praveen_gmat » Fri Aug 27, 2010 1:13 am
Two different chicken coops, Coop A and Coop B, contain only Leghorn and Marans chickens. A Leghorn chicken lays a certain average number of eggs per month, and a Marans chicken lays a certain average number of eggs per month. Coop A houses 10 Leghorn chickens and 8 Marans chickens and produces an average of 440 eggs in a month. Coop B houses 7 Leghorn chickens and 4 Marans chickens and produces an average of 280 eggs in a month. On average, how many more eggs per month does a Leghorn chicken lay than a Marans chicken?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 307
Joined: Sun Jul 11, 2010 7:52 pmFollowed by: 1 member
Thanked: 36 times
GMAT Score:640

by limestone » Fri Aug 27, 2010 2:06 am
Let's call the average no. of eggs that a Leghorn lays a month is "x"
"y" is that of Marans
From Coop A : 10x +8y = 440
From Coop B: 7x + 4y = 280, or we can say 14x + 8y = 560 ( multiply both sides to 2)
(14x + 8y) - (10x + 8y) = 560 -440
4x =120 or x =30
7x + 4y = 280, while x =30, then 7*30 + 4y = 280
4y =70, y = 17.5
x-y = 30-17.5 = 12.5
So 12.5 is No. of eggs per month a Leghorn chicken lays more than a Marans chicken.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 63
Joined: Sat Jul 24, 2010 10:29 amFollowed by: 1 member
Thanked: 1 times
GMAT Score:640

by praveen_gmat » Fri Aug 27, 2010 2:08 am
limestone wrote:Let's call the average no. of eggs that a Leghorn lays a month is "x"
"y" is that of Marans
From Coop A : 10x +8y = 440
From Coop B: 7x + 4y = 280, or we can say 14x + 8y = 560 ( multiply both sides to 2)
(14x + 8y) - (10x + 8y) = 560 -440
4x =120 or x =30
7x + 4y = 280, while x =30, then 7*30 + 4y = 280
4y =70, y = 17.5
x-y = 30-17.5 = 12.5
So 12.5 is No. of eggs per month a Leghorn chicken lays more than a Marans chicken.
Yeah you are right ..
You know what I did .. :(


10L + 8M
-------------- = 440 .... which implies that 5L + 4M = 3960
18


7L + 4M
------------- = 280 ....... which implies that 7L + 4M = 3080
11



This will give negative values ..
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 2326
Joined: Mon Jul 28, 2008 3:54 amFollowed by: 2 members
Thanked: 173 times
GMAT Score:710

by gmatmachoman » Fri Aug 27, 2010 2:49 am
limestone wrote:Let's call the average no. of eggs that a Leghorn lays a month is "x"
"y" is that of Marans
From Coop A : 10x +8y = 440
From Coop B: 7x + 4y = 280, or we can say 14x + 8y = 560 ( multiply both sides to 2)
(14x + 8y) - (10x + 8y) = 560 -440
4x =120 or x =30
7x + 4y = 280, while x =30, then 7*30 + 4y = 280
4y =70, y = 17.5
x-y = 30-17.5 = 12.5
So 12.5 is No. of eggs per month a Leghorn chicken lays more than a Marans chicken.
dude, i should admit i got this the way u did, but was bit wary how come eggs be in decimals..so hunned away from posting..

anyways good prblm...
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 63
Joined: Sat Jul 24, 2010 10:29 amFollowed by: 1 member
Thanked: 1 times
GMAT Score:640

by praveen_gmat » Fri Aug 27, 2010 2:50 am
gmatmachoman wrote:
limestone wrote:Let's call the average no. of eggs that a Leghorn lays a month is "x"
"y" is that of Marans
From Coop A : 10x +8y = 440
From Coop B: 7x + 4y = 280, or we can say 14x + 8y = 560 ( multiply both sides to 2)
(14x + 8y) - (10x + 8y) = 560 -440
4x =120 or x =30
7x + 4y = 280, while x =30, then 7*30 + 4y = 280
4y =70, y = 17.5
x-y = 30-17.5 = 12.5
So 12.5 is No. of eggs per month a Leghorn chicken lays more than a Marans chicken.
dude, i should admit i got this the way u did, but was bit wary how come eggs be in decimals..so hunned away from posting..

anyways good prblm...
@gmatmachoman

Yeah mate .. I think the problem is ridiculously stupid. :D
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Master | Next Rank: 500 Posts
Posts: 307
Joined: Sun Jul 11, 2010 7:52 pmFollowed by: 1 member
Thanked: 36 times
GMAT Score:640

by limestone » Fri Aug 27, 2010 5:08 am
The author is talking about the average no. of eggs that those chicken lay per month. So take an example:
First month, 1 Leghorn laid 13 eggs. Second month, 12 eggs. Third, 14 and forth 11.
Average eggs laid per month = (13+12+14+11)/4 = 12.5

That's it!!
Hope this could help.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Junior | Next Rank: 30 Posts
Posts: 21
Joined: Tue Apr 06, 2010 8:49 am

by sdotcruz » Fri Aug 27, 2010 6:20 am
limestone,

Why do we ignore the average formula in this problem? Are there some key words in the problem that lead us to the straight algebraic equation?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Master | Next Rank: 500 Posts
Posts: 307
Joined: Sun Jul 11, 2010 7:52 pmFollowed by: 1 member
Thanked: 36 times
GMAT Score:640

by limestone » Fri Aug 27, 2010 7:12 am
Two different chicken coops, Coop A and Coop B, contain only Leghorn and Marans chickens. A Leghorn chicken lays a certain average number of eggs per month, and a Marans chicken lays a certain average number of eggs per month. Coop A houses 10 Leghorn chickens and 8 Marans chickens and produces an average of 440 eggs in a month. Coop B houses 7 Leghorn chickens and 4 Marans chickens and produces an average of 280 eggs in a month. On average, how many more eggs per month does a Leghorn chicken lay than a Marans chicken?
The question gives us a confusing word: average. I'll take an example:
1 Leghorn lays average 15 eggs per month ( some months It lays 12, some it lays 16 or even 20, but the average eggs laid of all these months is 15, then the average formula is here)
So 2 Leghorns lay how many eggs on average per month? (15+15)/2 ? Not that way. It must be 15 *2 = 30
So 2 Leghorns & 1 Marans lay how many eggs on average per month? 15*2 + 10 ( 10 is the eggs laid by Maran on average per month)
Thus 10 Leghorns and 8 Marans lay: 10 * x + 8 * y , with x is the no. of eggs laid by one Leghorn on average per month, and y is that of Maran. We got 10x + 8y =440
And 7x +4y =280
Is it clear now?
Anyway, is it odd that an average chick can lay 440 eggs per month, or nearly 15 eggs per day?
Hope it help
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1