Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 03 May 2015, 05:08

### 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

# When a certain tree was first planted, it was 4 feet tall,

Author Message
TAGS:
Manager
Joined: 07 Oct 2005
Posts: 139
Location: Boston,MA
Followers: 1

Kudos [?]: 33 [0], given: 0

When a certain tree was first planted, it was 4 feet tall, [#permalink]  25 Dec 2007, 06:35
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
When a certain tree was first planted, it was 4 feet tall, and the height of the tree invreased by a constant amount each year for the next 6 years. At the end of the 6th year, the tree was 1/5 taller than it was at the end of the 4th year. By how many feet did the height of the tree increase each year
_________________

--gregspirited

VP
Joined: 09 Jul 2007
Posts: 1108
Location: London
Followers: 6

Kudos [?]: 74 [0], given: 0

Re: PS - Tree height [#permalink]  25 Dec 2007, 06:45
gregspirited wrote:
When a certain tree was first planted, it was 4 feet tall, and the height of the tree invreased by a constant amount each year for the next 6 years. At the end of the 6th year, the tree was 1/5 taller than it was at the end of the 4th year. By how many feet did the height of the tree increase each year

simplest method:

planted length: X=4
annual increase: Y

X,(X+Y),(X+2Y),(X+3Y),(X+4Y),(X+5Y),(X+6Y)

X+4Y+(X+4Y)/5=X+6Y
X+4Y=10
4+4Y=10
Y=3/2
Intern
Joined: 14 Dec 2007
Posts: 9
Followers: 0

Kudos [?]: 3 [0], given: 0

Re: PS - Tree height [#permalink]  25 Dec 2007, 13:26
Ravshonbek wrote:
gregspirited wrote:
When a certain tree was first planted, it was 4 feet tall, and the height of the tree invreased by a constant amount each year for the next 6 years. At the end of the 6th year, the tree was 1/5 taller than it was at the end of the 4th year. By how many feet did the height of the tree increase each year

simplest method:

planted length: X=4
annual increase: Y

X,(X+Y),(X+2Y),(X+3Y),(X+4Y),(X+5Y),(X+6Y)

X+4Y+(X+4Y)/5=X+6Y
X+4Y=10
4+4Y=10
Y=3/2

Yes this is the simplest approach. however final answer should be 2/3 but not 3/2.

X+4Y+(X+4Y)/5=X+6Y

X+4Y=10Y ==> X=6Y==>Y=X/6=4/6=2/3.
Intern
Joined: 07 Jan 2008
Posts: 1
Followers: 0

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

Re: PS - Tree height [#permalink]  07 Jan 2008, 10:59

X+4Y+(X+4Y)/5=X+6Y UNDERSTOOD
X+4Y=10 WHERE IS THIS 10 COMING FROM?....
4+4Y=10 WHAT HAPPEN WITH THE X?
Y=3/2
CEO
Joined: 29 Mar 2007
Posts: 2591
Followers: 16

Kudos [?]: 234 [0], given: 0

Re: PS - Tree height [#permalink]  07 Jan 2008, 11:15
gregspirited wrote:
When a certain tree was first planted, it was 4 feet tall, and the height of the tree invreased by a constant amount each year for the next 6 years. At the end of the 6th year, the tree was 1/5 taller than it was at the end of the 4th year. By how many feet did the height of the tree increase each year

4+6x=6/5(4+4x) --> 24/5+24x/5=4+6x --> 24/5-4=6x-24x/5 --> 24/5-20/5=30x/5-24x/5

4/5=6x/5 --> 20=30x --> x=2/3
Manager
Joined: 01 Jan 2008
Posts: 227
Schools: Booth, Stern, Haas
Followers: 1

Kudos [?]: 48 [0], given: 2

Re: PS - Tree height [#permalink]  07 Jan 2008, 11:24
gregspirited wrote:
When a certain tree was first planted, it was 4 feet tall, and the height of the tree invreased by a constant amount each year for the next 6 years. At the end of the 6th year, the tree was 1/5 taller than it was at the end of the 4th year. By how many feet did the height of the tree increase each year

4+5x=(4+3x)*1.2
4+5x=4.8+3.6x
1.4x=0.8
x=4/7
Manager
Joined: 01 Sep 2007
Posts: 103
Location: Astana
Followers: 1

Kudos [?]: 19 [0], given: 0

Re: PS - Tree height [#permalink]  07 Jan 2008, 11:38
correct reasoning, but note: it says at the end of the 6th and 4th years
i.e. 4+6x = (4+4x)*1.2
Intern
Joined: 07 Jan 2008
Posts: 21
Followers: 0

Kudos [?]: 3 [0], given: 0

Re: PS - Tree height [#permalink]  07 Jan 2008, 13:22

Let h be the constant increase in height each year.

So heights at end of each year => 4 + h, 4 + 2h, 4 + 3h, 4 + 4h, 4 + 5h, 4 + 6h

At end of 6 year, the tree is 1/5th taller than at the end of the 4th year, i.e.

( 4 + 6h ) – ( 4 + 4h ) = 1/5 * ( 4 + 4h)

=> 2h = 1/5 * ( 4 + 4h )
=> h = 2 / 3
Re: PS - Tree height   [#permalink] 07 Jan 2008, 13:22
Similar topics Replies Last post
Similar
Topics:
When a certain tree was first planted, it was 4 feet tall, 2 07 Dec 2007, 08:15
When a certain tree was first planted, it was 4 feet tall, 2 02 Aug 2006, 16:06
When a certain tree was first planted, it was 4 feet tall, 1 24 Apr 2006, 17:37
When a certain tree was first planted, it was 4 feet tall, 2 23 Apr 2006, 20:38
When a certain tree was first planted, it was 4 feet tall, 3 16 Nov 2005, 02:03
Display posts from previous: Sort by