Local kennel has cats and dogs in the ratio of 5:6. If there are 18 fewer cats than dogs, how many dogs are in the kennel?
A. 60
B. 74
C. 98
D. 108
E. 132
OA is D
OA says D but I solved and got E can an Expert shoe some solutions? Thanks
Fraction/Ratio
This topic has expert replies
-
- Moderator
- Posts: 772
- Joined: Wed Aug 30, 2017 6:29 pm
- Followed by:6 members
- EconomistGMATTutor
- GMAT Instructor
- Posts: 555
- Joined: Wed Oct 04, 2017 4:18 pm
- Thanked: 180 times
- Followed by:12 members
Hi Roland2rule,Local kennel has cats and dogs in the ratio of 5:6. If there are 18 fewer cats than dogs, how many dogs are in the kennel?
A. 60
B. 74
C. 98
D. 108
E. 132
OA is D
OA says D but I solved and got E can an Expert shoe some solutions? Thanks
Let's take a look at your question.
If C denotes cats and D denotes dogs, then,
$$\frac{C}{D}=\frac{5}{6}$$
$$6C=5D...(i)$$
If there are 18 fewer cats then dogs, we can write it as,
$$C=D-18$$
Substitute C in eq(i),
$$6\left(D-18\right)=5D$$
$$6D-108=5D$$
$$6D-5D=108$$
$$D=108$$
Therefore, Option D is correct.
Hope it helps.
I am available if you'd like any follow up.
GMAT Prep From The Economist
We offer 70+ point score improvement money back guarantee.
Our average student improves 98 points.
We offer 70+ point score improvement money back guarantee.
Our average student improves 98 points.
GMAT/MBA Expert
- Scott@TargetTestPrep
- GMAT Instructor
- Posts: 7243
- Joined: Sat Apr 25, 2015 10:56 am
- Location: Los Angeles, CA
- Thanked: 43 times
- Followed by:29 members
We can express the ratio of cats to dogs as 5x : 6x. We can create the equation:BTGmoderatorRO wrote:Local kennel has cats and dogs in the ratio of 5:6. If there are 18 fewer cats than dogs, how many dogs are in the kennel?
A. 60
B. 74
C. 98
D. 108
E. 132
OA is D
OA says D but I solved and got E can an Expert shoe some solutions? Thanks
6x - 5x = 18
x = 18
Thus, there are 6 x 18 =108 dogs in the kennel.
Answer: D
Scott Woodbury-Stewart
Founder and CEO
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews
GMAT/MBA Expert
- Brent@GMATPrepNow
- GMAT Instructor
- Posts: 16207
- Joined: Mon Dec 08, 2008 6:26 pm
- Location: Vancouver, BC
- Thanked: 5254 times
- Followed by:1268 members
- GMAT Score:770
Let D = # of DogsBTGmoderatorRO wrote:Local kennel has cats and dogs in the ratio of 5:6. If there are 18 fewer cats than dogs, how many dogs are in the kennel?
A. 60
B. 74
C. 98
D. 108
E. 132
Let C = # of Cats
There are 18 fewer cats than dogs.
So, C = D - 18
cats and dogs are in the ratio of 5:6
We get: C/D = 5/6
Cross multiply to get: 6C =5D
Take 6C =5D and replace C with D - 18 to get: 6(D - 18) = 5D
Expand: 6D - 108 = 5D
Subtract 6D from both sides to get: -108 = -D
So, D = 108
Answer: D
Cheers,
Brent