It is currently 21 Oct 2017, 23:45

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# A car traveling at a certain constant speed takes 2 seconds

Author Message
Senior Manager
Joined: 10 Mar 2008
Posts: 358

Kudos [?]: 376 [0], given: 0

A car traveling at a certain constant speed takes 2 seconds [#permalink]

### Show Tags

23 Sep 2008, 07:00
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

A car traveling at a certain constant speed takes 2 seconds longer to travel 1 kilometer than it would take to travel 1 kilometer at 75 kilometers per hour. At what speed, in kilometers per hour, is the car traveling?

A. 71.5
B. 72
C. 72.5
D. 73
E. 73.5

Could you please explan using RTD chart. I'm messing up the conversions for some reason. Thanks!

Kudos [?]: 376 [0], given: 0

SVP
Joined: 07 Nov 2007
Posts: 1792

Kudos [?]: 1063 [0], given: 5

Location: New York

### Show Tags

23 Sep 2008, 07:23
vksunder wrote:
A car traveling at a certain constant speed takes 2 seconds longer to travel 1 kilometer than it would take to travel 1 kilometer at 75 kilometers per hour. At what speed, in kilometers per hour, is the car traveling?

A. 71.5
B. 72
C. 72.5
D. 73
E. 73.5

Could you please explan using RTD chart. I'm messing up the conversions for some reason. Thanks!

D=RT

R= 75 km/hr = 75 /60*60 KM/sec
D= 1 km

T= D/R = 60*60/75 = 48sec

-----------

T2= 48+2= 50
R2*T2=D

R2= 1/50 km/se = 60*60/50 km/hr = 72

B
_________________

Smiling wins more friends than frowning

Kudos [?]: 1063 [0], given: 5

Director
Joined: 23 May 2008
Posts: 801

Kudos [?]: 84 [0], given: 0

### Show Tags

23 Sep 2008, 21:58
in the RTD chart I got

R*T=D
1) x*(t+2/3600)=1
2) 75*t=1, so t=1/75

sub t into equation 1
x(1/75 +2/3600) =1 x=72

Kudos [?]: 84 [0], given: 0

Re: Distance   [#permalink] 23 Sep 2008, 21:58
Display posts from previous: Sort by