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

It is currently 26 Jan 2020, 19:11

Close

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
Your Progress

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.

Close

Request Expert Reply

Confirm Cancel

A car first travels uphill at a speed of 54 kmph and then downhill at

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 60646
A car first travels uphill at a speed of 54 kmph and then downhill at  [#permalink]

Show Tags

New post 06 Jan 2020, 07:40
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

56% (02:44) correct 44% (02:02) wrong based on 41 sessions

HideShow timer Statistics

Senior Manager
Senior Manager
User avatar
G
Joined: 12 Sep 2017
Posts: 316
Re: A car first travels uphill at a speed of 54 kmph and then downhill at  [#permalink]

Show Tags

New post 14 Jan 2020, 19:24
1
Mine was super time consuming:

Avg.S = Td/Tt

63 = x+y/(x/54 + y/72)

3:4

Can someone please share any short cut?

Kind regards!
Manager
Manager
avatar
Status: Post MBA, working in the area of Development Finance
Joined: 09 Oct 2006
Posts: 110
Location: Africa
Re: A car first travels uphill at a speed of 54 kmph and then downhill at  [#permalink]

Show Tags

New post 14 Jan 2020, 23:29
1
jfranciscocuencag wrote:
Mine was super time consuming:

Avg.S = Td/Tt

63 = x+y/(x/54 + y/72)

3:4

Can someone please share any short cut?

Kind regards!


--------------------------------

It would be helpful to remove common factor to ease calculation

So, the equation becomes
7=x+y/(x/6 + y/8)
7*(x/6 + y/8)=x+y
7*(4x + 3y)=24*(x+y)
4x=3y
x/y=3/4
Intern
Intern
avatar
B
Joined: 06 Oct 2019
Posts: 3
GMAT ToolKit User
A car first travels uphill at a speed of 54 kmph and then downhill at  [#permalink]

Show Tags

New post 15 Jan 2020, 20:28
1
Use weighted average :

Given :
D S T
D1 54 D1/54
D2 72 D2/72

T1/T2 = (Avg - A1)/(A2 - Avg)

(D1/54)/(D2/72) = (63-54)/(72-63) = 9/9 = 1
=> D1/D2 = 3/4
Target Test Prep Representative
User avatar
V
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 9144
Location: United States (CA)
Re: A car first travels uphill at a speed of 54 kmph and then downhill at  [#permalink]

Show Tags

New post 21 Jan 2020, 09:50
1
Bunuel wrote:
A car first travels uphill at a speed of 54 kmph and then downhill at a speed of 72 kmph such that the average speed for the entire journey is 63 kmph. Find the ratio of the uphill distance to the downhill distance.

A. 1 : 1
B. 6 : 7
C. 7 : 8
D. 3 : 4
E. Cannot be determined


Let the uphill distance be x and the downhill distance be y (in kilometers). Then, it takes x/54 hours to climb uphill and y/72 hours to travel downhill. Using the average speed formula of total distance/total time, we ger:

(x + y)/(x/54 + y/72) = 63

x + y = 63(x/54 + y/72)

x + y = 63x/54 + 63y/72

x + y = 7x/6 + 7y/8

Multiplying each side by 24, we obtain:

24x + 24y = 4*7x + 3*7y

24x + 24y = 28x + 21y

3y = 4x

x/y = 3/4

Answer: D
_________________

Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
TTP - Target Test Prep Logo
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.

GMAT Club Bot
Re: A car first travels uphill at a speed of 54 kmph and then downhill at   [#permalink] 21 Jan 2020, 09:50
Display posts from previous: Sort by

A car first travels uphill at a speed of 54 kmph and then downhill at

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne