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

 It is currently 24 May 2019, 22:14

### 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

# John traveled 150 miles. What is the average speed of John on the trip

Author Message
TAGS:

### Hide Tags

Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 7372
GMAT 1: 760 Q51 V42
GPA: 3.82
John traveled 150 miles. What is the average speed of John on the trip  [#permalink]

### Show Tags

18 Feb 2017, 08:12
1
5
00:00

Difficulty:

55% (hard)

Question Stats:

52% (01:07) correct 48% (01:13) wrong based on 229 sessions

### HideShow timer Statistics

John traveled 150 miles. What is the average speed of John on the trip?

1) John traveled the first 100 miles at the rate of 50 miles per hour
2) John traveled the last 100 miles at the rate of 50 miles per hour

_________________
MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only \$149 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"
Director
Joined: 05 Mar 2015
Posts: 998
Re: John traveled 150 miles. What is the average speed of John on the trip  [#permalink]

### Show Tags

18 Feb 2017, 11:23
1
MathRevolution wrote:
John traveled 150 miles. What is the average speed of John on the trip?

1) John traveled the first 100 miles at the rate of 50 miles per hour
2) John traveled the last 100 miles at the rate of 50 miles per hour

1) no info on next 50 km...insuff
2) no info on first 50km...insuff

Combining we dont know the avg speed john maintained in the first 50 or last 50 or any else
we have combined avg speed of 100km as 50mph
thus insuff

Ans E
Intern
Joined: 17 Dec 2014
Posts: 24
Location: India
Schools: IMD Jan'18 (D)
GMAT 1: 710 Q48 V38
WE: Engineering (Energy and Utilities)
Re: John traveled 150 miles. What is the average speed of John on the trip  [#permalink]

### Show Tags

18 Feb 2017, 12:30
It is a 150 mile drive. If John traveled first 100 miles at 50 mph and he also traveled last 100 mile at 50 mph. That means he travelled the whole 150 mile at 50 mph !

Director
Joined: 05 Mar 2015
Posts: 998
Re: John traveled 150 miles. What is the average speed of John on the trip  [#permalink]

### Show Tags

18 Feb 2017, 13:03
beefcakeharsh wrote:
It is a 150 mile drive. If John traveled first 100 miles at 50 mph and he also traveled last 100 mile at 50 mph. That means he travelled the whole 150 mile at 50 mph !

U dont have the speed (ie speed may vary for those 100km) breakup

avg. speed = total distance/ total time
suppose for 100 km he may covered 75mph @ 75mph and another 25miles @ 25mph then his speed is 50mph
or,
100miles covered in 15 miles @ 10mph and another 85 miles @ 170mph then again his speed is 50mph.

also notice such variance is speed may be for either of the 100miles covered in both options.
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 7372
GMAT 1: 760 Q51 V42
GPA: 3.82
Re: John traveled 150 miles. What is the average speed of John on the trip  [#permalink]

### Show Tags

19 Feb 2017, 18:43
==> In the original condition, he travels the total 150 miles by dividing it to two trips of 50 miles each. Hence, since there are 6 variables, E is most likely to be the answer. In order for C to be the answer, there must be a word “constant rate” mentioned.

_________________
MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only \$149 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"
Intern
Joined: 11 Apr 2018
Posts: 12
Location: India
Concentration: General Management, Strategy
GPA: 3.9
Re: John traveled 150 miles. What is the average speed of John on the trip  [#permalink]

### Show Tags

17 Jul 2018, 21:56
Combining both (1) and (2), it can be inferred that the avg speed is 50 mph. I think the answer is C.
Manager
Joined: 07 Aug 2018
Posts: 110
Location: United States (MA)
GMAT 1: 560 Q39 V28
GMAT 2: 670 Q48 V34
Re: John traveled 150 miles. What is the average speed of John on the trip  [#permalink]

### Show Tags

28 Sep 2018, 08:10
MathRevolution wrote:
==> In the original condition, he travels the total 150 miles by dividing it to two trips of 50 miles each. Hence, since there are 6 variables, E is most likely to be the answer. In order for C to be the answer, there must be a word “constant rate” mentioned.

1) John traveled the first 100 miles at the rate of 50 miles per hour
2) John traveled the last 100 miles at the rate of 50 miles per hour

Dear MathRevolution,

I do not understand why the correct answer it E.

Booth statements gives us the actual rate and not any average. So we know for sure that in the first 100miles his speed was always 50mph. The same goes for the last 100 miles. Therefore we know for sure that he was driving at 50mph the whole 150 miles trip. Or where did I go wrong?
_________________
Intern
Joined: 12 May 2018
Posts: 37
GMAT 1: 640 Q43 V35
GMAT 2: 700 Q48 V38
GPA: 3.76
WE: Research (Pharmaceuticals and Biotech)
Re: John traveled 150 miles. What is the average speed of John on the trip  [#permalink]

### Show Tags

28 Sep 2018, 16:08
the question mentions traveling at rate of 50 mile/hr. It does not say average speed of first 100 miles is 50 mile/hr.
The answer is C. Since first 100 miles he travels at 50 mile/hr and last 100 also at 50 mile/hr, which means that during any time of the trip, he is travelling at 50 mile/hr.

Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 7372
GMAT 1: 760 Q51 V42
GPA: 3.82
Re: John traveled 150 miles. What is the average speed of John on the trip  [#permalink]

### Show Tags

03 Oct 2018, 10:33
dprchem wrote:
Combining both (1) and (2), it can be inferred that the avg speed is 50 mph. I think the answer is C.

Let a, b and c be numbers of hours for the first 50 miles, the second 50 miles and the last 50 miles.

If a = 1, b = 1 and c = 1, then the average speed of the trip is 150 / 3 = 50 miles/hr.
If a = 0.5, b = 1.5 and c = 0.5, then the average speed of the trip is 150 / ( 0.5 + 1.5 + 0.5 ) = 150/2.5 = 60 miles/hr.

Since we don't have a unique solution, E is the answer.
_________________
MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only \$149 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 7372
GMAT 1: 760 Q51 V42
GPA: 3.82
Re: John traveled 150 miles. What is the average speed of John on the trip  [#permalink]

### Show Tags

03 Oct 2018, 10:35
T1101 wrote:
MathRevolution wrote:
==> In the original condition, he travels the total 150 miles by dividing it to two trips of 50 miles each. Hence, since there are 6 variables, E is most likely to be the answer. In order for C to be the answer, there must be a word “constant rate” mentioned.

1) John traveled the first 100 miles at the rate of 50 miles per hour
2) John traveled the last 100 miles at the rate of 50 miles per hour

Dear MathRevolution,

I do not understand why the correct answer it E.

Booth statements gives us the actual rate and not any average. So we know for sure that in the first 100 miles his speed was always 50 mph. The same goes for the last 100 miles. Therefore we know for sure that he was driving at 50 mph the whole 150 miles trip. Or where did I go wrong?

Since the second 50 miles are overlapped for both conditions. The following is the explanation.

Let a, b and c be numbers of hours for the first 50 miles, the second 50 miles and the last 50 miles.

If a = 1, b = 1 and c = 1, then the average speed of the trip is 150 / 3 = 50 miles/hr.
If a = 0.5, b = 1.5 and c = 0.5, then the average speed of the trip is 150 / ( 0.5 + 1.5 + 0.5 ) = 150/2.5 = 60 miles/hr.

Since we don't have a unique solution, E is the answer.
_________________
MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only \$149 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"
Manager
Joined: 27 Apr 2011
Posts: 52
Location: India
GMAT Date: 06-13-2017
John traveled 150 miles. What is the average speed of John on the trip  [#permalink]

### Show Tags

03 Oct 2018, 13:28
Poor quality question;gmat always gives enough clarity on question.

Posted from my mobile device
_________________
Hope it's clear.
_________________
Please +1 KUDO if my post helps. Thank you.
John traveled 150 miles. What is the average speed of John on the trip   [#permalink] 03 Oct 2018, 13:28
Display posts from previous: Sort by