Events & Promotions
|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Jun 0808:00 PM EDT
-10:00 PM EDT
Master the GMAT with expert live instruction, a personalized study plan, and real-time support. Includes 40 hours of online classes plus 6 months of access to the TTP GMAT OnDemand video course. Mon/Wed June 8, 2026 →August 12, 2026 8:00pm-10:00pm EST
Jun 1006:00 AM PDT
-06:15 PM PDT
Register for the GMAT Club Virtual MBA Spotlight Fair – the world’s premier event for serious MBA candidates. This is your chance to hear directly from Admissions Directors at nearly every Top 30 MBA program..- Jun 10
10:00 AM PDT
-11:00 AM PDT
Scoring 715 on the GMAT Focus Edition requires more than just learning formulas, memorizing concepts, or solving hundreds of questions. In this episode, Nishant shares how he improved his GMAT preparation by focusing on application of concepts, and more. 
Jun 1111:00 AM EDT
-01:00 PM EDT
TTP GMAT OnDemand gives serious students 400+ hours of expert video instruction, the full TTP course, AI support, weekly office hours, and a 715+ score guarantee—all built for elite GMAT score improvement.
13 May 2025, 21:19
Kudos
Bookmarks
Cats: 36
Dogs: 44
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
35%
(medium)
Question Stats:
71% (01:58) correct
29%
(02:27)
wrong
based on 560
sessions
History
Date
Time
Result
Not Attempted Yet
A pet store is home to only cats and dogs, and the average weight of each animal at the store is 42 pounds. If the average weight of cats is 20 pounds and the average weight of dogs is 60 pounds, which of the following could be the number of cats and the number of dogs at the store (select one number in each column)?
| Cats | Dogs | |
| 11 | ||
| 16 | ||
| 22 | ||
| 27 | ||
| 36 | ||
| 44 |
ShowHide Answer
Official Answer
Cats: 36
Dogs: 44
14 May 2025, 01:11
Kudos
Bookmarks
The store has only cats and dogs, with an overall average weight of 42 pounds, cats averaging 20 pounds, and dogs averaging 60 pounds.
Using the mixture method, we set up a weighted average to find the ratio of cats to dogs.
42
/----\
/------ \
/----------\
Cats--------Dogs
20-----------60
Calculate the differences to find the ratio:
\(\text{Distance from cats to mixture} = 42 - 20 = 22\)
\(\text{Distance from dogs to mixture} = 60 - 42 = 18\)
The ratio of dogs to cats is the inverse of these differences:
\(\text{Dogs : Cats} = 22 : 18 = 11 : 9\)
The total number of animals must be a multiple of \(11 + 9 = 20\), and the number of dogs and cats must match the ratio \(11 : 9\) and be in the provided options.
Other pairs don’t yield the 11:9 ratio or fit the options. For example, 22 cats and 27 dogs give a total of 49, not a multiple of 20, and the ratio 27:22 ≠ 11:9.
Answer: 36 cats, 44 dogs
Using the mixture method, we set up a weighted average to find the ratio of cats to dogs.
42
/----\
/------ \
/----------\
Cats--------Dogs
20-----------60
Calculate the differences to find the ratio:
\(\text{Distance from cats to mixture} = 42 - 20 = 22\)
\(\text{Distance from dogs to mixture} = 60 - 42 = 18\)
The ratio of dogs to cats is the inverse of these differences:
\(\text{Dogs : Cats} = 22 : 18 = 11 : 9\)
The total number of animals must be a multiple of \(11 + 9 = 20\), and the number of dogs and cats must match the ratio \(11 : 9\) and be in the provided options.
| Cats | Dogs | Total Animals | Ratio Check |
| 36 | 44 | 36 + 44 = 80 | 80 ÷ 20 = 4; Cats: 4 × 9 = 36, Dogs: 4 × 11 = 44. Matches ratio and options. |
Other pairs don’t yield the 11:9 ratio or fit the options. For example, 22 cats and 27 dogs give a total of 49, not a multiple of 20, and the ratio 27:22 ≠ 11:9.
Answer: 36 cats, 44 dogs
12 Jul 2025, 11:23
Kudos
Bookmarks
1. The question asks us to find out a working pair of the number of cats and dogs.
2. Let these two values be x and y, respectively. In addition, the weights of the cats and dogs are \(c_1, c_2, ..., c_x\) and \(d_1, d_2, ..., d_y\), respectively.
3. Now, using the formula for averages, we can write down the following equations:
- \(42 = \frac{c_1 + c_2 + ... + c_x + d_1 + d_2 + ... + d_y}{x + y}\).
- \(20 = \frac{c_1 + c_2 + ... + c_x}{x} \rightarrow 20x = c_1 + c_2 + ... + c_x\).
- \(60 = \frac{d_1 + d_2 + ... + d_y}{y} \rightarrow 60y = d_1 + d_2 + ... + d_y\).
4. The first equation can be rewritten, \(42 = \frac{c_1 + c_2 + ... + c_x + d_1 + d_2 + ... + d_y}{x + y} = \frac{20x + 60y}{x + y} \rightarrow 42x + 42y = 20x + 60y \rightarrow 22x = 18y \rightarrow x = \frac{9}{11} * y\).
5. In order for x to be an integer, y must be divisible by 11, which leaves 3 options to check:
- y = 11. \(x = \frac{9}{11} * 11 = 9\), which doesn't work.
- y = 22. \(x = \frac{9}{11} * 22 = 18\), which doesn't work.
- y = 44. \(x = \frac{9}{11} * 44 = 36\), which works.
6. Our answer will be: Cats - 36 and Dogs - 44.
2. Let these two values be x and y, respectively. In addition, the weights of the cats and dogs are \(c_1, c_2, ..., c_x\) and \(d_1, d_2, ..., d_y\), respectively.
3. Now, using the formula for averages, we can write down the following equations:
- \(42 = \frac{c_1 + c_2 + ... + c_x + d_1 + d_2 + ... + d_y}{x + y}\).
- \(20 = \frac{c_1 + c_2 + ... + c_x}{x} \rightarrow 20x = c_1 + c_2 + ... + c_x\).
- \(60 = \frac{d_1 + d_2 + ... + d_y}{y} \rightarrow 60y = d_1 + d_2 + ... + d_y\).
4. The first equation can be rewritten, \(42 = \frac{c_1 + c_2 + ... + c_x + d_1 + d_2 + ... + d_y}{x + y} = \frac{20x + 60y}{x + y} \rightarrow 42x + 42y = 20x + 60y \rightarrow 22x = 18y \rightarrow x = \frac{9}{11} * y\).
5. In order for x to be an integer, y must be divisible by 11, which leaves 3 options to check:
- y = 11. \(x = \frac{9}{11} * 11 = 9\), which doesn't work.
- y = 22. \(x = \frac{9}{11} * 22 = 18\), which doesn't work.
- y = 44. \(x = \frac{9}{11} * 44 = 36\), which works.
6. Our answer will be: Cats - 36 and Dogs - 44.
