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

 It is currently 23 Jan 2020, 12:13

### 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

# Cars J and K are making the trip from City A to City B. Car J departs

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 60627
Cars J and K are making the trip from City A to City B. Car J departs  [#permalink]

### Show Tags

13 Nov 2019, 06:05
00:00

Difficulty:

65% (hard)

Question Stats:

56% (02:04) correct 44% (02:57) wrong based on 70 sessions

### HideShow timer Statistics

Cars J and K are making the trip from City A to City B. Car J departs from City A 15 minutes after Car K does, and both cars travel along the same route. If Car K travels at a constant speed that is 80% the constant speed of Car J, then how many minutes will elapse before Car J catches up to Car K?

A. 20
B. 45
C. 60
D. 75
E. 1230

Are You Up For the Challenge: 700 Level Questions

_________________
Manager
Joined: 10 Dec 2017
Posts: 177
Location: India
Cars J and K are making the trip from City A to City B. Car J departs  [#permalink]

### Show Tags

13 Nov 2019, 06:21
Bunuel wrote:
Cars J and K are making the trip from City A to City B. Car J departs from City A 15 minutes after Car K does, and both cars travel along the same route. If Car K travels at a constant speed that is 80% the constant speed of Car J, then how many minutes will elapse before Car J catches up to Car K?

A. 20
B. 45
C. 60
D. 75
E. 1230

Are You Up For the Challenge: 700 Level Questions

Speed of Car J= X
Speed of Car K=0.8X
distance travelled by Car K in 15 minutes= 15*0.8X
=12X
So Car J will cover this 12X distance relative to Car K in time "t"
speed*time=distance
(X-0.8X)*t=12X
t=60 minutes
C:)
VP
Joined: 19 Oct 2018
Posts: 1294
Location: India
Re: Cars J and K are making the trip from City A to City B. Car J departs  [#permalink]

### Show Tags

13 Nov 2019, 14:19
$$V_J : V_K= 5:4$$

$$T_J : T_K= 4:5$$

$$T_K - T_J=5x - 4x=15$$

$$T_J= 4x= 4*15=60$$

Bunuel wrote:
Cars J and K are making the trip from City A to City B. Car J departs from City A 15 minutes after Car K does, and both cars travel along the same route. If Car K travels at a constant speed that is 80% the constant speed of Car J, then how many minutes will elapse before Car J catches up to Car K?

A. 20
B. 45
C. 60
D. 75
E. 1230

Are You Up For the Challenge: 700 Level Questions
Senior Manager
Joined: 21 Jun 2017
Posts: 396
Location: India
Concentration: Finance, Economics
Schools: IIM
GMAT 1: 620 Q47 V30
GPA: 3
WE: Corporate Finance (Commercial Banking)
Cars J and K are making the trip from City A to City B. Car J departs  [#permalink]

### Show Tags

14 Nov 2019, 23:33
1
Then how many minutes will elapse before Car J catches up to Car K

(t+15)K = (t)J and K=(4/5)*J . Hence t is 60 . But we are asked of elapsed time so add 15 minutes to it. Answer = 60+15 = 75.
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 9117
Location: United States (CA)
Re: Cars J and K are making the trip from City A to City B. Car J departs  [#permalink]

### Show Tags

17 Nov 2019, 20:28
Bunuel wrote:
Cars J and K are making the trip from City A to City B. Car J departs from City A 15 minutes after Car K does, and both cars travel along the same route. If Car K travels at a constant speed that is 80% the constant speed of Car J, then how many minutes will elapse before Car J catches up to Car K?

A. 20
B. 45
C. 60
D. 75
E. 1230

Are You Up For the Challenge: 700 Level Questions

Let r = the speed of Car J, so 0.8r = the speed of Car K. Let’s also let t = Car J’s travel time, in hours; this means that (t + ¼) is Car K’s travel time (because 15 minutes = ¼ hour). We can create the equation:

Car K’s distance = Car J’s distance

(0.8r)(t + 1/4) = rt

0.8(t + 0.25) = t

0.8t + 0.2 = t

0.2 = 0.2t

1 = t

Since 1 hour = 60 minutes, choice C is the correct answer.

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
181 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: 23 Jul 2015
Posts: 79
Re: Cars J and K are making the trip from City A to City B. Car J departs  [#permalink]

### Show Tags

17 Nov 2019, 22:15
1
Why isn't the answer 75? Don't have to count the 15 min delay as well?
Re: Cars J and K are making the trip from City A to City B. Car J departs   [#permalink] 17 Nov 2019, 22:15
Display posts from previous: Sort by