Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 43862

During a twoyear period, the water level in a lake decreased by 20 pe [#permalink]
Show Tags
10 May 2017, 01:37
Question Stats:
86% (00:45) correct 14% (00:38) wrong based on 42 sessions
HideShow timer Statistics



Intern
Joined: 12 Nov 2016
Posts: 16

Re: During a twoyear period, the water level in a lake decreased by 20 pe [#permalink]
Show Tags
10 May 2017, 02:06
Initial level = w After the 1st year, water level reduces by 20%. Hence, the resulting water level would be 0.8w After the 2nd year, the water level increased by 10%. Hence, the resultant water level would be 1.1*0.8w= 0.88w Hence, Option D should be the correct answer.



VP
Joined: 22 May 2016
Posts: 1342

During a twoyear period, the water level in a lake decreased by 20 pe [#permalink]
Show Tags
10 May 2017, 07:45
Bunuel wrote: During a twoyear period, the water level in a lake decreased by 20 percent by the end of the first year and increased by 10 percent by the end of the second year. If the lake began the period with a water level of w feet, what was the level, in feet, by the end of the period?
A. 1.2w B. 1.1w C. 0.9w D. 0.88w E. 0.8w Decrease by 20% [1.20] = .80 Increase by 10% = [1+.10] 1.10 (.8)(1.1) = .88 Multiply that product by original value, w ==> .88w Answer D
_________________
At the still point, there the dance is.  T.S. Eliot Formerly genxer123



Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 1986

Re: During a twoyear period, the water level in a lake decreased by 20 pe [#permalink]
Show Tags
12 May 2017, 12:40
Bunuel wrote: During a twoyear period, the water level in a lake decreased by 20 percent by the end of the first year and increased by 10 percent by the end of the second year. If the lake began the period with a water level of w feet, what was the level, in feet, by the end of the period?
A. 1.2w B. 1.1w C. 0.9w D. 0.88w E. 0.8w We are given that the lake began at a level of w feet and that the level decreased 20% and then increased 10%. So the ending level is: w x 0.8 x 1.1 = 0.88w Answer: D
_________________
Jeffery Miller
Head of GMAT Instruction
GMAT Quant SelfStudy Course
500+ lessons 3000+ practice problems 800+ HD solutions



Director
Joined: 04 Dec 2015
Posts: 696
Location: India
Concentration: Technology, Strategy
WE: Information Technology (Consulting)

Re: During a twoyear period, the water level in a lake decreased by 20 pe [#permalink]
Show Tags
16 May 2017, 04:42
During a twoyear period, the water level in a lake decreased by 20 percent by the end of the first year and increased by 10 percent by the end of the second year. If the lake began the period with a water level of w feet, what was the level, in feet, by the end of the period? A. 1.2w B. 1.1w C. 0.9w D. 0.88w E. 0.8w Water level = w After first year water level decreased by 20% = 80% of w After second year water level increased by 10% = 110% of 80% of w Therefore water level by the end of period = \(\frac{110}{100}\) x \(\frac{80}{100}\) x w = \(\frac{88}{100}\) x w = 0.88w Answer D... _________________ Kindly press "+1 Kudos" to appreciate



Board of Directors
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 3326
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)

Re: During a twoyear period, the water level in a lake decreased by 20 pe [#permalink]
Show Tags
16 May 2017, 07:32
Bunuel wrote: During a twoyear period, the water level in a lake decreased by 20 percent by the end of the first year and increased by 10 percent by the end of the second year. If the lake began the period with a water level of w feet, what was the level, in feet, by the end of the period?
A. 1.2w B. 1.1w C. 0.9w D. 0.88w E. 0.8w Let, initial water level be "w" Water level after 1st year = \(80/100*w\) \(= 0.80w\) Water level after 2nd year = \(\frac{0.80w*110}{100}\) \(= 0.88w\) Thus, level of water in feet after 2nd year is 0.88w
_________________
Thanks and Regards
Abhishek....
PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS
How to use Search Function in GMAT Club  Rules for Posting in QA forum  Writing Mathematical Formulas Rules for Posting in VA forum  Request Expert's Reply ( VA Forum Only )



Director
Joined: 13 Mar 2017
Posts: 562
Location: India
Concentration: General Management, Entrepreneurship
GPA: 3.8
WE: Engineering (Energy and Utilities)

Re: During a twoyear period, the water level in a lake decreased by 20 pe [#permalink]
Show Tags
16 May 2017, 07:37
Bunuel wrote: During a twoyear period, the water level in a lake decreased by 20 percent by the end of the first year and increased by 10 percent by the end of the second year. If the lake began the period with a water level of w feet, what was the level, in feet, by the end of the period?
A. 1.2w B. 1.1w C. 0.9w D. 0.88w E. 0.8w Initial water level = w feet. at the end of first year = 0.8 w at the end of 2nd year = 0.8 x 1.1 w = 0.88 w
_________________
CAT 99th percentiler : VA 97.27  DILR 96.84  QA 98.04  OA 98.95
MBA Social Network : WebMaggu
Appreciate by Clicking +1 Kudos ( Lets be more generous friends.)




Re: During a twoyear period, the water level in a lake decreased by 20 pe
[#permalink]
16 May 2017, 07:37






