GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 17 Oct 2018, 05:19

### 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

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# The ratio of toddlers to infants at a day care center is 7 to 3. If

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 49969
The ratio of toddlers to infants at a day care center is 7 to 3. If  [#permalink]

### Show Tags

19 Oct 2016, 23:33
00:00

Difficulty:

5% (low)

Question Stats:

88% (01:29) correct 12% (02:25) wrong based on 166 sessions

### HideShow timer Statistics

The ratio of toddlers to infants at a day care center is 7 to 3. If twelve more infants join the day care to change the ratio to 7 to 5, how many toddlers are there at this day care center?

A. 24
B. 36
C. 42
D. 72
E. 120

_________________
Current Student
Joined: 13 Jun 2015
Posts: 37
Location: India
Concentration: General Management, Operations
GMAT 1: 680 Q48 V35
GMAT 2: 680 Q50 V32
GPA: 3
WE: Project Management (Manufacturing)
Re: The ratio of toddlers to infants at a day care center is 7 to 3. If  [#permalink]

### Show Tags

20 Oct 2016, 02:38
1

initial ratio is 7:3
let them be 7x and 3x

12 added to 3x; new ratio will be 7x/(3x+12) = 7:5

solving the equation we get 7x = 42
_________________

There is no secret ingredient !
It's just you !!!

Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4094
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
Re: The ratio of toddlers to infants at a day care center is 7 to 3. If  [#permalink]

### Show Tags

20 Oct 2016, 08:06
Bunuel wrote:
The ratio of toddlers to infants at a day care center is 7 to 3. If twelve more infants join the day care to change the ratio to 7 to 5, how many toddlers are there at this day care center?

A. 24
B. 36
C. 42
D. 72
E. 120

5x - 3x = 12

So, 2x = 6

hence no of toddlers is 6*7 =42

Answer will be (C) 42

_________________

Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )

CEO
Joined: 12 Sep 2015
Posts: 3000
Re: The ratio of toddlers to infants at a day care center is 7 to 3. If  [#permalink]

### Show Tags

20 Oct 2016, 08:52
2
Top Contributor
Bunuel wrote:
The ratio of toddlers to infants at a day care center is 7 to 3. If twelve more infants join the day care to change the ratio to 7 to 5, how many toddlers are there at this day care center?

A. 24
B. 36
C. 42
D. 72
E. 120

Here's a different solution.
If the original toddlers to infant ratio is 7 to 3, then there are many different possible scenarios. Here are a few possibilities:
- 7 toddlers and 3 infants
- 14 toddlers and 6 infants
- 21 toddlers and 9 infants
- 28 toddlers and 12 infants
.
.
.
IMPORTANT: Notice that the number of toddlers is always divisible by 7
So, the correct answer must be divisible by 7

When we check the answer choices, we see that we can ELIMINATE A, B, D and E

RELATED VIDEO

_________________

Brent Hanneson – GMATPrepNow.com

Sign up for our free Question of the Day emails

Intern
Joined: 26 Aug 2016
Posts: 6
Location: United States
GMAT 1: 670 Q49 V32
GPA: 2.62
Re: The ratio of toddlers to infants at a day care center is 7 to 3. If  [#permalink]

### Show Tags

20 Oct 2016, 17:38
The ratio of toddlers to infants at a day care center is 7 to 3. If twelve more infants join the day care to change the ratio to 7 to 5, how many toddlers are there at this day care center?

A. 24
B. 36
C. 42
D. 72
E. 120

t/i = 7/3

t/i+12 =7/5

5t =7i + 84

3t = 7i

subsitute , t =84/2 =42
Manager
Joined: 29 Aug 2008
Posts: 110
Re: The ratio of toddlers to infants at a day care center is 7 to 3. If  [#permalink]

### Show Tags

20 Oct 2016, 22:42
Current ratio of Toddler to Infant = 7:3

After addition of 12 infants:

$$\frac{7x}{(3x+12)}$$ = $$\frac{7}{5}$$

X = 6

So No of Toddlers = 7*6 = 42.

Option C
Intern
Joined: 11 May 2015
Posts: 5
Location: India
Concentration: General Management, Finance
Re: The ratio of toddlers to infants at a day care center is 7 to 3. If  [#permalink]

### Show Tags

21 Oct 2016, 10:05
Let, Toddler be x and Infant be y

From given Information,
x/y=7/3

Hence, x=7y/3----(1)

Now, 12 more infants are added which change the ratio to 7/5

x/(y+12)=7/5----(2)

Using value of x from equation (1)

7y/3(y+12)=7/5

Solving we get,

y=18

Substituting value in the equation (1)
We Get,

x=42.

Ans:- Hence Number of Toddlers is 42.

----------------------------------------------
Alternative Solution(Shortcut ):

If we observer, the value of infant is changing and value of toddler is constant in the ratio which is 7.

Only option which is multiple of 7 is 42.

Once we get this we can cross verify it using equations (1) and (2).
Current Student
Status: DONE!
Joined: 05 Sep 2016
Posts: 384
The ratio of toddlers to infants at a day care center is 7 to 3. If  [#permalink]

### Show Tags

27 Oct 2016, 20:07
7x/(3x+12) = 7/5

35x=7(3x+12)
35x=21x+84
14x=84
x=6

7x= # of toddlers --> 7(6) = 42
Non-Human User
Joined: 09 Sep 2013
Posts: 8431
Re: The ratio of toddlers to infants at a day care center is 7 to 3. If  [#permalink]

### Show Tags

22 Apr 2018, 17:40
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: The ratio of toddlers to infants at a day care center is 7 to 3. If &nbs [#permalink] 22 Apr 2018, 17:40
Display posts from previous: Sort by

# The ratio of toddlers to infants at a day care center is 7 to 3. If

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.