Mar 20 07:00 AM PDT  09:00 AM PDT Join a FREE 1day workshop and learn how to ace the GMAT while keeping your fulltime job. Limited for the first 99 registrants. Mar 20 09:00 PM EDT  10:00 PM EDT Strategies and techniques for approaching featured GMAT topics. Wednesday, March 20th at 9 PM EDT Mar 23 07:00 AM PDT  09:00 AM PDT Christina scored 760 by having clear (ability) milestones and a trackable plan to achieve the same. Attend this webinar to learn how to build trackable milestones that leverage your strengths to help you get to your target GMAT score.
Author 
Message 
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 53734

Three children, Doug, Darla, and Dave, all collect marbles. The number
[#permalink]
Show Tags
28 Aug 2017, 23:37
Question Stats:
70% (02:17) correct 30% (02:20) wrong based on 107 sessions
HideShow timer Statistics



Senior PS Moderator
Joined: 26 Feb 2016
Posts: 3361
Location: India
GPA: 3.12

Three children, Doug, Darla, and Dave, all collect marbles. The number
[#permalink]
Show Tags
29 Aug 2017, 01:21
If the number of Doug's marbles is \(\frac{2}{5}\)(40%) of the number of Darla's marbles, Assume Darla has 10 marbles, making the number of marbles Doug has 4. It has also been given that the Doug has 4 times as many marbles as Dave. Therefore, Dave will have 1 marble. The average of Doug and Dave's marbles is \(\frac{(1+4)}{2} = \frac{5}{2}\) Since we have been asked how many times is the number of Darla's marbles to the average, it must be \(\frac{10}{{\frac{5}{2}}\) = \(\frac{10*2}{5}\) = 4(Option E)
_________________
You've got what it takes, but it will take everything you've got



Intern
Joined: 25 Jan 2013
Posts: 21
Concentration: Marketing, Strategy
GPA: 3.64

Re: Three children, Doug, Darla, and Dave, all collect marbles. The number
[#permalink]
Show Tags
29 Aug 2017, 01:35
Bunuel wrote: Three children, Doug, Darla, and Dave, all collect marbles. The number of Doug’s marbles is 2/5 the number of Darla’s marbles. However, Doug has 4 times as many marbles as Dave does. The number of Darla’s marbles is how many times the average of Doug and Dave’s marbles?
A. 1/4 B. 1/2 C. 3/2 D. 2 E. 4 let's assume Darla has 20 marbles. So, Dough has =(2/5)*20= 8 marbles and Dave has 2 Mabels the average of Dough and Dave marbles is 5. So, Darla has 4 times the average of Doug and Dave’s marbles.
_________________
pressing +1 kudos is a nice way to say thanks



Senior SC Moderator
Joined: 22 May 2016
Posts: 2558

Three children, Doug, Darla, and Dave, all collect marbles. The number
[#permalink]
Show Tags
29 Aug 2017, 19:19
Bunuel wrote: Three children, Doug, Darla, and Dave, all collect marbles. The number of Doug’s marbles is 2/5 the number of Darla’s marbles. However, Doug has 4 times as many marbles as Dave does. The number of Darla’s marbles is how many times the average of Doug and Dave’s marbles?
A. 1/4 B. 1/2 C. 3/2 D. 2 E. 4 I picked numbers, my math went awry, and I switched to algebra. Doug is the common element. Darla = A Doug = B Dave = C B's marbles = \(\frac{2}{5}\)A, so A = \(\frac{5}{2}\)B B has 4 times as many marbles as C. B = 4C, and C = \(\frac{B}{4}\) Average of B and C: \((\frac{4}{4}\)B + \(\frac{B}{4})\) *\(\frac{1}{2}\) = \(\frac{5}{8}B\) The number of marbles that A has is how many times the average of B and C’s marbles? \(\frac{\frac{5}{2}B}{\frac{5}{8}B}\) = \(\frac{5}{2}\) * \(\frac{8}{5}\) = 4 Answer E
_________________
And above all, watch with glittering eyes the whole world around you because the greatest secrets are always hidden in the most unlikely places. Those who don't believe in magic will never find it. —Roald Dahl



Target Test Prep Representative
Status: Head GMAT Instructor
Affiliations: Target Test Prep
Joined: 04 Mar 2011
Posts: 2825

Re: Three children, Doug, Darla, and Dave, all collect marbles. The number
[#permalink]
Show Tags
01 Sep 2017, 12:11
Bunuel wrote: Three children, Doug, Darla, and Dave, all collect marbles. The number of Doug’s marbles is 2/5 the number of Darla’s marbles. However, Doug has 4 times as many marbles as Dave does. The number of Darla’s marbles is how many times the average of Doug and Dave’s marbles?
A. 1/4 B. 1/2 C. 3/2 D. 2 E. 4 We can let Doug’s marbles = A, Darla’s marbles = B, and Dave’s marbles = C. Thus: A = (2/5)B (5/2)A = B B = 5A/2 and A = 4C A/4 = C Let’s find the average number of Doug’s and Dave’s marbles: (A + A/4)/2 = (5A/4)/2 = 5A/8. Thus, the number of Darla’s marbles is (5A/2)/(5A/8) = 5A/2 x 8/5A = 4 times the average number of Doug’s and Dave’s marbles. Answer: E
_________________
5star 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



Manager
Joined: 19 Apr 2017
Posts: 57

Re: Three children, Doug, Darla, and Dave, all collect marbles. The number
[#permalink]
Show Tags
20 Feb 2019, 08:21
Since the names starts with D, i am using their last letter Doug= G, Darla= A Dave= E
Using Propotions 5G=2A > G:A =2:5 x2 =4:10 G=4E > G:E = 4:1 Make G = 4 to combine the two equations
G:A:E = 4:10:1
Average of G and E = (G+E)/2 = 5/2
how many times is G=10 will be equal to 5/2=2.5 > 10/2.5= 4 = E




Re: Three children, Doug, Darla, and Dave, all collect marbles. The number
[#permalink]
20 Feb 2019, 08:21






