Herd of Goats

Expert replies

kartikshah: Master | Next Rank: 500 Posts; Posts: 156; Joined: Sun Jul 15, 2012 12:03 pmFollowed by: 1 member; Location: New York, USA; Thanked: 34 times

by kartikshah » Sun Jul 22, 2012 5:20 am

A herd of goats consists of A males and B females. In that herd, half of the goats that have horns are females. If C goats of the herd do not have horns, then the total number of male goats in the herd that do NOT have horns, in terms of A, B and C is -
A. (A-B+C)/2
B. (A-B-C)/2
C. (A+B+C)/2
D. (A+B-C)/2
E. (2A-B+C)/2

Source: Master GMAT

I quite enjoyed solving this question correctly. I hope others get it right too! OA will be shared after a few answers begin to come in.
(BTW, Master GMAT's free content has some nice questions on sets)

Like this post

Source: Beat The GMAT — Problem Solving | Sun Jul 22, 2012 5:20 am

theCEO: Master | Next Rank: 500 Posts; Posts: 363; Joined: Sun Oct 17, 2010 3:24 pmFollowed by: 3 members; Thanked: 115 times

by theCEO » Sun Jul 22, 2012 5:34 am

imo D

Like this post

eagleeye: Legendary Member; Posts: 520; Joined: Sat Apr 28, 2012 9:12 pmFollowed by: 49 members; Thanked: 339 times; GMAT Score:770

by eagleeye » Sun Jul 22, 2012 5:41 am

kartikshah wrote:A herd of goats consists of A males and B females. In that herd, half of the goats that have horns are females. If C goats of the herd do not have horns, then the total number of male goats in the herd that do NOT have horns, in terms of A, B and C is -
A. (A-B+C)/2
B. (A-B-C)/2
C. (A+B+C)/2
D. (A+B-C)/2
E. (2A-B+C)/2

Source: Master GMAT

I quite enjoyed solving this question correctly. I hope others get it right too! OA will be shared after a few answers begin to come in.
(BTW, Master GMAT's free content has some nice questions on sets)

Total Goats = T = A+B
Goats without horns =C
Goats with horns = A+B-C
half of these are males
So male goats with horns = (A+B-C)/2
So male goats without horns = total males - horned males = A - (A+B-C)/2 = (A-B+C)/2.

A is correct.

Alternatively, Let A=2, B=2 and C=4.
Then Goats with horns = 4-4 = 0. So both male goats do not have horns. Let's check the option that gives us 2.
Now test the options:

(2-2+4)/2 = 2 (works)
(2-2-4)/2 = -ve (NO)
(2+2+4)/2 = 4 (NO)
(2+2-4)/2 = 0 (NO)
(4-2+4)/2 = 3 (NO)

A is correct.

Like this post

theCEO: Master | Next Rank: 500 Posts; Posts: 363; Joined: Sun Oct 17, 2010 3:24 pmFollowed by: 3 members; Thanked: 115 times

by theCEO » Sun Jul 22, 2012 5:47 am

eagleeye wrote:
kartikshah wrote:A herd of goats consists of A males and B females. In that herd, half of the goats that have horns are females. If C goats of the herd do not have horns, then the total number of male goats in the herd that do NOT have horns, in terms of A, B and C is -
A. (A-B+C)/2
B. (A-B-C)/2
C. (A+B+C)/2
D. (A+B-C)/2
E. (2A-B+C)/2

Source: Master GMAT

I quite enjoyed solving this question correctly. I hope others get it right too! OA will be shared after a few answers begin to come in.
(BTW, Master GMAT's free content has some nice questions on sets)
Total Goats = T = A+B
Goats without horns =C
Goats with horns = A+B-C
half of these are males
So male goats with horns = (A+B-C)/2
So male goats without horns = total males - horned males = A - (A+B-C)/2 = (A-B+C)/2.

A is correct.

Alternatively, Let A=2, B=2 and C=4.
Then Goats with horns = 4-4 = 0. So both male goats do not have horns. Let's check the option that gives us 2.
Now test the options:

(2-2+4)/2 = 2 (works)
(2-2-4)/2 = -ve (NO)
(2+2+4)/2 = 4 (NO)
(2+2-4)/2 = 0 (NO)
(4-2+4)/2 = 3 (NO)

A is correct.

Its funny how the word NOT is capitalized and I did not see it. Hope I get back my eyesight before the day of the exam

Like this post

tisrar02: Master | Next Rank: 500 Posts; Posts: 130; Joined: Fri Apr 20, 2012 8:13 amFollowed by: 4 members; Location: Toronto, Ontario; Thanked: 16 times; GMAT Score:650

by tisrar02 » Mon Jul 23, 2012 6:23 pm

A=10
B=10
Assume C=4

Half of the goats with horns are females= 2 Females have horns
That means 2 Males have horns.

What is the total number of Males without horns?

10-2=8---> NUMBER WE WANT!!!!!

(A-B+C)/2= (10-10+16)/2= 8

Answer- A

I would recommend going through all the answer choices to see if any other answers yield the number we want.

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

560 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review