It is currently 21 Oct 2020, 14:15

### 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

# Louise is three times as old as Mary. Mary is twice as old a

Author Message
TAGS:
Retired Moderator
Joined: 07 Jun 2014
Posts: 4803
GRE 1: Q167 V156
WE: Business Development (Energy and Utilities)
Followers: 173

Kudos [?]: 2970 [0], given: 394

Louise is three times as old as Mary. Mary is twice as old a [#permalink]  19 Aug 2018, 03:41
Expert's post
00:00

Question Stats:

85% (01:21) correct 15% (01:38) wrong based on 40 sessions
Louise is three times as old as Mary. Mary is twice as old as Natalie. If Louise is L years old, what is the average (arithmetic mean) age of the three women, in terms of L?

(A) $$\frac{L}{3}$$
(B) $$\frac{L}{2}$$
(C) $$\frac{2L}{3}$$
(D) $$\frac{L}{4}$$
(E) $$\frac{L}{6}$$
[Reveal] Spoiler: OA

_________________

Sandy
If you found this post useful, please let me know by pressing the Kudos Button

Try our free Online GRE Test

GRE Instructor
Joined: 10 Apr 2015
Posts: 3871
Followers: 158

Kudos [?]: 4632 [1] , given: 70

Re: Louise is three times as old as Mary. Mary is twice as old a [#permalink]  21 Aug 2018, 11:36
1
KUDOS
Expert's post
sandy wrote:
Louise is three times as old as Mary. Mary is twice as old as Natalie. If Louise is L years old, what is the average (arithmetic mean) age of the three women, in terms of L?

(A) $$\frac{L}{3}$$
(B) $$\frac{L}{2}$$
(C) $$\frac{2L}{3}$$
(D) $$\frac{L}{4}$$
(E) $$\frac{L}{6}$$

GIVEN: Louise is L years old

Louise is three times as old as Mary
This also means that Mary is 1/3 as old as Louise
Louise's age = L
So, Mary's age = (1/3)L = L/3

Mary is twice as old as Natalie.
This also means that Natalie is 1/2 as old as Mary
Mary's age = L/3
So, Natalie's age = (1/2)(L/3) = L/6

What is the average (arithmetic mean) age of the three women, in terms of L?
Average age = (sum of all 3 ages)/3

Sum of all 3 ages = L + L/3 + L/6
= 6L/6 + 2L/6 + L/6 [I rewrote each fraction with a common denominator of 6]
= 9L/6
= 3L/2

So, average age = (3L/2)/3
= L/2

Cheers,
Brent
_________________

Brent Hanneson – Creator of greenlighttestprep.com
If you enjoy my solutions, you'll like my GRE prep course.

Director
Joined: 22 Jun 2019
Posts: 517
Followers: 5

Kudos [?]: 106 [0], given: 161

Re: Louise is three times as old as Mary. Mary is twice as old a [#permalink]  13 Oct 2019, 15:12
sandy wrote:
Louise is three times as old as Mary. Mary is twice as old as Natalie. If Louise is L years old, what is the average (arithmetic mean) age of the three women, in terms of L?

(A) $$\frac{L}{3}$$
(B) $$\frac{L}{2}$$
(C) $$\frac{2L}{3}$$
(D) $$\frac{L}{4}$$
(E) $$\frac{L}{6}$$

L = 3M ; M = 2N ; L = L all of are in terms of their given value.

Now L = 3M = 3* 2N(where M=2N) = 6N So, L=6N;

Therefore, L=6N ; M=2N ; L=N(lets assume L=N); and there sum of 6N+2N+N=9N
Now we need to divide by 3 as they want AVERAGE So 9N/3=3N
BUT we know that L=6N/3N = L/2
_________________

New to the GRE, and GRE CLUB Forum?
Posting Rules: QUANTITATIVE | VERBAL

Questions' Banks and Collection:
ETS: ETS Free PowerPrep 1 & 2 All 320 Questions Explanation. | ETS All Official Guides
3rd Party Resource's: All In One Resource's | All Quant Questions Collection | All Verbal Questions Collection | Manhattan 5lb All Questions Collection
Books: All GRE Best Books
Scores: Average GRE Score Required By Universities in the USA
Tests: All Free & Paid Practice Tests | GRE Prep Club Tests
Extra: Permutations, and Combination
Vocab: GRE Vocabulary

Intern
Joined: 10 Oct 2020
Posts: 13
Followers: 0

Kudos [?]: 7 [0], given: 0

Re: Louise is three times as old as Mary. Mary is twice as old a [#permalink]  10 Oct 2020, 04:59
Solved this by substituting numbers

Lets consider L = 60, then M = 20 , and N = 10

Average age of 3 women = (60+20+10)/3 = 90/3 = 30

Average in terms of L = 60/2 = 30

Ans: B
Re: Louise is three times as old as Mary. Mary is twice as old a   [#permalink] 10 Oct 2020, 04:59
Display posts from previous: Sort by