GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 19 Feb 2020, 20:00 ### 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

#### Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.  # John can eat x doughnuts in y minutes. If Chen can eat doughnuts three

Author Message
TAGS:

### Hide Tags

Math Expert V
Joined: 02 Sep 2009
Posts: 61302
John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags 00:00

Difficulty:   35% (medium)

Question Stats: 76% (01:55) correct 24% (01:53) wrong based on 73 sessions

### HideShow timer Statistics

Competition Mode Question

John can eat x doughnuts in y minutes. If Chen can eat doughnuts three times as fast as John, how many doughnuts will John and Chen eat in an hour?

(A) $$15*\frac{4x}{4}$$

(B) $$60*\frac{3x}{y}$$

(C) $$15*\frac{16x}{y}$$

(D) $$60*\frac{x}{y}$$

(E) $$60*\frac{x}{3y}$$

Are You Up For the Challenge: 700 Level Questions

_________________
CEO  D
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 3155
Location: India
GMAT: INSIGHT
Schools: Darden '21
WE: Education (Education)
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
John can eat x doughnuts in y minutes.

Chen eats three time as fast as John

i.e. Chen can eat 3x doughnuts in y minutes.

i.e. Chen and John can eat (x+3x) = 4x donughnuts in y minutes

i.e. in 1 hour (60 minutes) they can eat (4x/y)*60 = 240x/y doughnuts every hour

i.e. 15(16x/y) doughnuts every hour

_________________
Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

ACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION
HEC & IMD School Moderator P
Status: Preparing for GMAT
Joined: 16 Dec 2018
Posts: 724
Location: Italy
Schools: HEC'22 (J), IMD '22
WE: Engineering (Manufacturing)
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
In Y mins, John eat doughnuts = X
so, in 1 min, John will eat = $$\frac{X}{Y}$$

Similarly, in 1 min, Chen will eat = $$\frac{3X}{Y}$$ ... (eats Three times faster).

Together they will eat in 1 min = $$\frac{X}{Y}+\frac{3X}{Y}$$ = $$\frac{4X}{Y}$$

So, in 1 hour (60 mins), they will eat - $$\frac{4X}{Y} * 60$$ = $$240 * \frac{4X}{Y}$$ which is equivalent to our option 'C' - $$15*\frac{16X}{Y}$$
_________________
Director  V
Joined: 30 Sep 2017
Posts: 660
GMAT 1: 720 Q49 V40 GPA: 3.8
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
John can eat (x/y) doughnuts in 1 minute. In an hour, he can eat 60*(x/y) doughnuts.

Chen can eat 3*(x/y) doughnuts in 1 minute. In an hour, he can eat 180*(x/y) doughnuts.

Together, they eat (60+180)*(x/y) = 240*(x/y) = 15*16*(x/y) doughnuts in an hour

Posted from my mobile device
VP  P
Joined: 24 Nov 2016
Posts: 1218
Location: United States
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
Quote:
John can eat x doughnuts in y minutes. If Chen can eat doughnuts three times as fast as John, how many doughnuts will John and Chen eat in an hour?

(A) 15∗4x/4
(B) 60∗3x/y
(C) 15∗16x/y
(D) 60∗x/y
(E) 60∗x/3y

r=td
john rate: x/y d/min
chen rate: 3x/y d/min
j+c 1 hr: 60min * (x/y+3x/y) = 60(4x/y) = 240x/y = 15(16x/y)

Ans (C)
VP  V
Joined: 20 Jul 2017
Posts: 1322
Location: India
Concentration: Entrepreneurship, Marketing
WE: Education (Education)
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
John can eat x doughnuts in y minutes
--> Number of doughnuts John can eat in 1 minute = $$\frac{x}{y}$$

Chen can eat doughnuts three times as fast as John
--> Number of doughnuts Chen can eat in 1 minute = $$3*\frac{x}{y} = \frac{3x}{y}$$

Number of doughnuts John & Chen can eat in 1 minute together = $$\frac{x}{y} + \frac{3x}{y} = \frac{4x}{y}$$

In 1 hour = 60 minutes = $$60*\frac{4x}{y} = 15*\frac{16x}{y}$$

Option C
Intern  B
Joined: 24 Jan 2020
Posts: 8
Location: United States (TX)
Schools: McCombs
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
John's rate: r=x/y
Chen's rate: r=3x/y
Combined rate: 4x/y

Solution: YummyDonuts = 60 * (4x/y) = 15 * (16x/y) <-- Recognizing that these two are the same is the tricky part I think.

Director  P
Joined: 25 Jul 2018
Posts: 549
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
John: x doughnuts in y minutes
—> $$\frac{x}{y}$$ —doughnuts per minute

Chen : $$3(\frac{x}{y})$$
Together in an hour:
—> $$(\frac{x}{y}+ 3*\frac{x}{y})*60 = 240(\frac{x}{y})$$

Only answer choice C matches this answer ( $$15*\frac{16x}{y})$$

Posted from my mobile device
Senior Manager  P
Joined: 27 Feb 2014
Posts: 339
Location: India
GMAT 1: 570 Q49 V20 GPA: 3.97
WE: Engineering (Education)
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
John can eat x doughnuts in y minutes.
Rate of John = (x/y) min

If Chen can eat doughnuts three times as fast as John
Rate of Chen = 3x/y min

Using RT=W equation
Combined rate is 4x/y min

In 1 hour they will eat 4x/y * 60 = 240x/y

Checking the options
C is correct
Manager  G
Joined: 30 Jul 2019
Posts: 101
Location: Viet Nam
Concentration: Technology, Entrepreneurship
GPA: 2.79
WE: Education (Non-Profit and Government)
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
Quote:
John can eat x doughnuts in y minutes. If Chen can eat doughnuts three times as fast as John, how many doughnuts will John and Chen eat in an hour?

(A) $$15∗\frac{4x}{4}$$

(B) $$60∗\frac{3x}{y}$$

(C) $$15∗\frac{16x}{y}$$

(D) $$60∗\frac{x}{y}$$

(E) $$60∗\frac{x}{3y}$$

John can eat x doughnuts in y minutes
=> The number of doughnuts John can eat in an hour is $$x*\frac{60}{y}$$
Chen can eat doughnuts three times as fast as John
=> The number of doughnuts Chen can eat in an hour is $$3x*\frac{60}{y}$$
=> The number of doughnuts John and Chen will eat in an hour is $$4x*\frac{60}{y} = 15∗\frac{16x}{y}$$
==>>> Choice C
Manager  S
Joined: 26 Dec 2017
Posts: 54
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
Ans: C

John in 1 min= x/y
Chen in 1 min=3x/y

so in 60 min= 60(x/y + 3x/y)=240 x/y= 15 16x/y
GMAT Club Legend  V
Joined: 18 Aug 2017
Posts: 5940
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
2 methods;
method 1 :

Rate of John ; x/y and Rate of Chen ; 3x/y

in 60 mins they would be able to eat ; 4x/y * 60 = 240*x/y or say 15 * 16 x/y
IMO C

method 2
let rate of John be x=5 donuts per y= 30 mins ; i.e 10 donuts per hour
now rate of Chen would be 30 donuts per hour ;
total donuts eaten John + chen ; 40
substitute x & y in 15 * 16 * 5/ 30 ; IMO C;

John can eat x doughnuts in y minutes. If Chen can eat doughnuts three times as fast as John, how many doughnuts will John and Chen eat in an hour?
SVP  D
Joined: 03 Jun 2019
Posts: 2005
Location: India
GMAT 1: 690 Q50 V34 WE: Engineering (Transportation)
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
John eats x/y donuts / minute
Chen eats 3x/y donuts /minute
Together they eat 4x/y donuts/minute = 60 * 4x/y = 15* 16x/y donuts / hour

IMO C

Posted from my mobile device
CR Forum Moderator P
Joined: 18 May 2019
Posts: 706
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
In y minutes, John can eat x doughnuts. Chen can eat 3x in y minutes.
Hence Chen and John can eat a total of 4x doughnuts in y minutes.
We are to determine how many doughnuts Chen and John can eat in 60 minutes. With the above information, we can reduce this question to a simple case of ratio and proportions.
y minutes : 4x
60 minutes : z
z=4x * 60/y = (15 * 16x)/y

Manager  B
Joined: 14 Sep 2019
Posts: 160
Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  [#permalink]

### Show Tags

1
John can eat doughnuts per minute = x/y
Chen can eat doughnuts per minute =3x/y, (As Chen can eat doughnuts three times as fast as John)
John and Chen eat doughnuts in one minute = x/y +3x/y = 4x/y
John and Chen eat doughnuts in an hour (60 minutes) = 4x*60/y = 240x/y = 15*16/y (15*16 =240)(C) Re: John can eat x doughnuts in y minutes. If Chen can eat doughnuts three   [#permalink] 26 Jan 2020, 09:08
Display posts from previous: Sort by

# John can eat x doughnuts in y minutes. If Chen can eat doughnuts three  