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

 It is currently 22 Aug 2019, 05:23

### 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

# During a trip that they took together, Carmen, Juan, Maria, a

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 57238
During a trip that they took together, Carmen, Juan, Maria, a  [#permalink]

### Show Tags

21 Jun 2018, 09:07
2
Top Contributor
4
00:00

Difficulty:

5% (low)

Question Stats:

96% (00:59) correct 4% (01:12) wrong based on 1092 sessions

### HideShow timer Statistics

During a trip that they took together, Carmen, Juan, Maria, and Rafael drove an average (arithmetic mean) of 80 miles each. Carmen drove 72 miles, Juan drove 78 miles, and Maria drove 83 miles. How many miles did Rafael drive?

A. 80

B. 82

C. 85

D. 87

E. 89

NEW question from GMAT® Official Guide 2019

(PS10002)

_________________
CEO
Joined: 12 Sep 2015
Posts: 3913
During a trip that they took together, Carmen, Juan, Maria, a  [#permalink]

### Show Tags

21 Jun 2018, 18:33
Top Contributor
Bunuel wrote:
During a trip that they took together, Carmen, Juan, Maria, and Rafael drove an average (arithmetic mean) of 80 miles each. Carmen drove 72 miles, Juan drove 78 miles, and Maria drove 83 miles. How many miles did Rafael drive?

A. 80

B. 82

C. 85

D. 87

E. 89

NEW question from GMAT® Official Guide 2019

(PS10002)

Let x = the number of miles Rafael drove

Average = 80
So, (72 + 78 + 83 + x)/4 = 80
Multiply both sides by 4 to get: 72 + 78 + 83 + x = 320
Simplify: 233 + x = 320
Solve: x = 87

RELATED VIDEO

_________________
Test confidently with gmatprepnow.com
Math Expert
Joined: 02 Aug 2009
Posts: 7754
Re: During a trip that they took together, Carmen, Juan, Maria, a  [#permalink]

### Show Tags

21 Jun 2018, 19:00
Bunuel wrote:
During a trip that they took together, Carmen, Juan, Maria, and Rafael drove an average (arithmetic mean) of 80 miles each. Carmen drove 72 miles, Juan drove 78 miles, and Maria drove 83 miles. How many miles did Rafael drive?

A. 80

B. 82

C. 85

D. 87

E. 89

NEW question from GMAT® Official Guide 2019

(PS10002)

Total distance = average * number = 80*4=320..
So C+J+R+M=320....72+78+R+83=320
R=320-233=87

D
_________________
Manager
Joined: 01 Aug 2017
Posts: 223
Location: India
GMAT 1: 500 Q47 V15
GPA: 3.4
WE: Information Technology (Computer Software)
During a trip that they took together, Carmen, Juan, Maria, a  [#permalink]

### Show Tags

21 Jun 2018, 19:02
4
During a trip that they took together, Carmen, Juan, Maria, and Rafael drove an average (arithmetic mean) of 80 miles each. Carmen drove 72 miles, Juan drove 78 miles, and Maria drove 83 miles. How many miles did Rafael drive?

A. 80

B. 82

C. 85

D. 87

E. 89

NEW question from GMAT® Official Guide 2019

(PS10002)

This is an easy to approach problem. Let me try without using pen & paper here.

As we all know Average is $$\frac{sum of all the elements}{no of elements}$$

Average given is - 80.

We will make note of - how far each value is from average?

C - 8
J - 2
M - $$-3$$ ( -ve sign denote that it is more than average)

Add up all this value - 10-3 =7.

In order to make an average of 80. the Rafael should travel 7 miles more than average.

Rafael travels : 80 + 7 = 87.

All of the above calculation can be done in mind because it is very small number.

Ans - D.

Let me know if it doesn't help, I would elaborate it.
_________________
If it helps you please press Kudos!

Thank You
Sudhanshu
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 7420
Location: United States (CA)
Re: During a trip that they took together, Carmen, Juan, Maria, a  [#permalink]

### Show Tags

23 Jul 2018, 18:41
1
Bunuel wrote:
During a trip that they took together, Carmen, Juan, Maria, and Rafael drove an average (arithmetic mean) of 80 miles each. Carmen drove 72 miles, Juan drove 78 miles, and Maria drove 83 miles. How many miles did Rafael drive?

A. 80

B. 82

C. 85

D. 87

E. 89

We can create the equation:

(72 + 78 + 83 + x)/4 = 80

233 + x = 320

x = 87

Alternate Solution:

Carmen drove 8 miles under the average, Juan drove 2 miles under the average and Maria drove 3 miles above the average. If we add these up, we get -8 + (-2) + 3 = -7; which means we are 7 miles under the average. Therefore, Rafael must drive 7 miles over the average to keep the average at 80 miles. Thus, Rafael drove 80 + 7 = 87 miles.

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Manager
Joined: 12 Dec 2017
Posts: 77
Location: India
Schools: Yale '19, GMBA '20, XLRI
GMAT 1: 660 Q46 V35
GPA: 3.8
Re: During a trip that they took together, Carmen, Juan, Maria, a  [#permalink]

### Show Tags

13 Jan 2019, 20:35
A little confusion here!
Isn't the average speed equal to total distance / total time ?

How can we divide the sum of miles traveled by 4?

Posted from my mobile device
Intern
Joined: 04 Apr 2019
Posts: 1
Re: During a trip that they took together, Carmen, Juan, Maria, a  [#permalink]

### Show Tags

21 Apr 2019, 04:17
Arithmetic mean for 4 people was 80, so we multiply 80*4=320, and 320 is the sum of results for 4 people. now we subtract 320-(72+78+83)=87
_________________
Winter is coming
Intern
Joined: 17 Dec 2018
Posts: 4
GMAT 1: 650 Q47 V38
Re: During a trip that they took together, Carmen, Juan, Maria, a  [#permalink]

### Show Tags

21 Apr 2019, 08:19
[quote="Bunuel"]During a trip that they took together, Carmen, Juan, Maria, and Rafael drove an average (arithmetic mean) of 80 miles each. Carmen drove 72 miles, Juan drove 78 miles, and Maria drove 83 miles. How many miles did Rafael drive?

A. 80

B. 82

C. 85

D. 87

E. 89

Hi,

According to stem, total miles driven: 80*4=320 miles

Now,
subtract the miles driven of the other drivers to find the miles driven for Rafael

320 miles - (72+78+83) miles= 87 miles.
OA: D
Intern
Joined: 09 Nov 2018
Posts: 3
Re: During a trip that they took together, Carmen, Juan, Maria, a  [#permalink]

### Show Tags

21 Apr 2019, 08:23
[quote="Bunuel"]During a trip that they took together, Carmen, Juan, Maria, and Rafael drove an average (arithmetic mean) of 80 miles each. Carmen drove 72 miles, Juan drove 78 miles, and Maria drove 83 miles. How many miles did Rafael drive?

A. 80

B. 82

C. 85

D. 87

E. 89

Total miles driven = 80*4 people = 320 miles
Miles driven by Carmen, Juan and Maria = 72+78+83 = 233 miles
Miles driven by Rafael = 320 - 233 = 87 miles
Hence, OA: D
Manager
Joined: 25 Sep 2018
Posts: 60
Re: During a trip that they took together, Carmen, Juan, Maria, a  [#permalink]

### Show Tags

10 May 2019, 12:04
Bunuel wrote:
During a trip that they took together, Carmen, Juan, Maria, and Rafael drove an average (arithmetic mean) of 80 miles each. Carmen drove 72 miles, Juan drove 78 miles, and Maria drove 83 miles. How many miles did Rafael drive?

A. 80

B. 82

C. 85

D. 87

E. 89

NEW question from GMAT® Official Guide 2019

(PS10002)

Total =80*4=320
=>72+78+83+R=320
=>R=320-233=87

Posted from my mobile device
Re: During a trip that they took together, Carmen, Juan, Maria, a   [#permalink] 10 May 2019, 12:04
Display posts from previous: Sort by