The population of a small beach town on Australia's east coast grows b

Question

The population of a small beach town on Australia's east coast grows by 50% from May 1 to June 1 and then grows by another 50% from June 1 to July 1. The population then decreases by 11.11% from July 1 to August 1. By approximately what percentage has the population grown from May 1 to August 1?

a) 50%
b) 90%
c) 100%
d) 200%
e) 225%

Please assist with above problem.

a) 50%
b) 90%
c) 100%
d) 200%
e) 225%

Please assist with above problem.

abhimahna · Answer

Are we sure OA marked is correct?

I solved this way :

Let the population in May = 2x
June = 3x
July = 4.5x

July = 8/9 * 4.5x = 4x(Note : 11.11% is 1/9, so left over would be 8/9)

Thus , change from May to Aug = 2x, which is 100% of the original. Hence, I marked C.

Please let me know where am I missing.

vponde · Answer

This is not right,

1.5 * 1.5 * 0.989 * x ~ 2,22x

2,22x is a 122% increase, so the best option is C

KarishmaB · Answer

PopAug1 = PopMay1 * (3/2) * (3/2) * (8/9) = PopMay1 * 2 Population of August is twice the population of May. So it has grown by 100%. Answer (C) Check this post for successive percentage changes: https://www.gmatclub.com/forum/veritas-prep-resource-links-no-longer-available-399979.html#/2011/0 ... e-changes/

Vinayak Shenoy · Answer

Say the population was 100 to begin with
From May 1 to June 1 it increased by 50% i.e., population now is 150.
From June 1 to July 1 again it increased by 50% i.e., population now is 150+75= 225
Population decreased by 11.11% from July 1 to august 1 i.e., 225*(8/9)=200
% change in population from April 1 to August 1 is {(200-100)/100}*100= 100%

rhine29388 · Answer

consider the population of beach town on 1 st may be 100
on 1 st june it increased by 50 % so the population is 1.5 * 100 = 150
on 1 st july it increased by another 50 % = 1.5 * 150 = 225
on 1 st august it decresed by 11.11 % or it became  \frac{8}{9}  of its value

so  \frac{8}{9}  * 225 = 200

clearly its a 100 % increase
correct answer - C

gauravk · Answer

We can do this using successive percentage change formula.

If there is a change of a% followed by b% the overall change = a + b + ab/100 (in case of decrease use -a etc)

First change 50% and then another 50% increase

50 + 50 + 50*50/100 = 125%

Now we can pair this 125% and -11.11%

125 - 11.11 - 125*11.11/100

which will be approx 100%

HTH

JeffTargetTestPrep · Answer

We can let the initial population = n.

After the town grows by 50%, then another 50%, and then decreases by 11.11%, we have:

n(3/2)(3/2)(8/9) = 72n/36 = 2n

Let’s determine the percentage increase:

(2n - n)/n x 100 = n/n x 100 = 100%

Answer: C

EMPOWERgmatRichC · Answer

Hi All,

This question can be solved either Algebraically or by TESTing VALUES. Here's how you can TEST VALUES to get to the solution:

Population on May 1 = 100 
Population on June 1 = 100 + (.5)(100) = 150 
Population on July 1 = 150 + (.5)(150) = 225

Population on August 1 = 225 - (1/9)(225) = 200

The question asks for the percent increase in population during that time.

Percentage Change = (new - old)/old = (200 - 100)/100 = 1/1 = 100%

Final Answer:  C

GMAT assassins aren't born, they're made, 
Rich

bumpbot · Answer

Automated notice from GMAT Club BumpBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

The population of a small beach town on Australia's east coast grows b

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

The population of a small beach town on Australia's east coast grows b

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards