## Welcome to BrainDen.com - Brain Teasers Forum

 Welcome to BrainDen.com - Brain Teasers Forum. Like most online communities you must register to post in our community, but don't worry this is a simple free process. To be a part of BrainDen Forums you may create a new account or sign in if you already have an account. As a member you could start new topics, reply to others, subscribe to topics/forums to get automatic updates, get your own profile and make new friends. Of course, you can also enjoy our collection of amazing optical illusions and cool math games. If you like our site, you may support us by simply clicking Google "+1" or Facebook "Like" buttons at the top. If you have a website, we would appreciate a little link to BrainDen. Thanks and enjoy the Den :-)
Guest Message by DevFuse

5 replies to this topic

### #1 brhan

brhan

• Members
• 466 posts

Posted 20 February 2008 - 05:41 PM

A car travels downhill at 72 km per hr, on the level at 63 km per hr, and uphill at 56 km per hr. The car takes 4 hours to travel from town A to town B. The return trip takes 4 hours and 40 minutes. What is the distance between the two towns.
• 0

### #2 Enlightened

Enlightened

• Members
• 124 posts

Posted 20 February 2008 - 06:38 PM

Spoiler for solution

• 0

### #3 PolishNorbi

PolishNorbi

• Members
• 120 posts

Posted 20 February 2008 - 06:53 PM

Spoiler for Spoiler

Edited by PolishNorbi, 20 February 2008 - 06:53 PM.

• 0

### #4 bonanova

bonanova

bonanova

• Moderator
• 6153 posts
• Gender:Male
• Location:New York

Posted 20 February 2008 - 09:31 PM

A car travels downhill at 72 km per hr, on the level at 63 km per hr, and uphill at 56 km per hr. The car takes 4 hours to travel from town A to town B. The return trip takes 4 hours and 40 minutes. What is the distance between the two towns.

Can we assume that the road from A to B has a constant grade?
• 0

Vidi vici veni.

### #5 Aatif

Aatif

Junior Member

• Members
• 72 posts

Posted 21 February 2008 - 02:37 AM

Can we assume that the road from A to B has a constant grade?

Bonanova, I think you don't need to assume that A to B have constant grade, but you do need to assume (or maybe its given) that he drives at constant speed of 72kmph downhill, regardless of the gradient and 56kmph uphill regardless of the gradient .

• 0

### #6 brhan

brhan

• Members
• 466 posts

Posted 21 February 2008 - 12:26 PM

Can we assume that the road from A to B has a constant grade?

You may assume that the car travels at constant speed during the three events. That is, at constant speed of 72 km per hr on the downhill, at 63 km per hr on the level, and at 56 km per hr on the uphill.
• 0

#### 0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users