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

 It is currently 10 Feb 2016, 16:45

### 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

# problem on ages

Author Message
TAGS:
Intern
Joined: 05 Jul 2010
Posts: 3
Followers: 0

Kudos [?]: 1 [0], given: 0

problem on ages [#permalink]  05 Jul 2010, 11:03
00:00

Difficulty:

(N/A)

Question Stats:

75% (02:54) correct 25% (00:00) wrong based on 5 sessions
five years ago,Beth's age was three times that of Amy.Ten years ago ,Beth's age was one half that of Chelsea.If "C" represents Chelsea's current age ,which of the following represents Amy's current age?

A)(c/6)+5
B)2c
C)(c-10)/3
D)3c-5
E)(5c/3)-10
Manager
Joined: 22 Oct 2009
Posts: 242
GMAT 1: 760 Q49 V44
GPA: 3.88
Followers: 6

Kudos [?]: 75 [0], given: 1

Re: problem on ages [#permalink]  05 Jul 2010, 11:13
dineshboinapalli wrote:
five years ago,Beth's age was three times that of Amy.Ten years ago ,Beth's age was one half that of Chelsea.If "C" represents Chelsea's current age ,which of the following represents Amy's current age?

A)(c/6)+5
B)2c
C)(c-10)/3
D)3c-5
E)(5c/3)-10

Were did you get this problem from?

I worked it out algabreically and got
$$A = \frac{(C+30)}{6}$$

I then tried to plug in numbers to make sure I didn't make any stupid mistakes.
If B = 20, then
A = 5+5 = 10
C = 30

I then plugged in these values and none of the answers were correct. As I suspected, my algebraic answer was correct
$$A = \frac{(C+30)}{6} = \frac{(30+30)}{6} = 10$$

I believe that these answer choices are all incorrect.
Manager
Joined: 22 Oct 2009
Posts: 242
GMAT 1: 760 Q49 V44
GPA: 3.88
Followers: 6

Kudos [?]: 75 [0], given: 1

Re: problem on ages [#permalink]  05 Jul 2010, 11:16
Also, I believe this should be in the Quant forum under the Problem Solving sub-forum.

Mods - would you mind moving this to get better visibility?
Intern
Joined: 05 Jul 2010
Posts: 3
Followers: 0

Kudos [?]: 1 [0], given: 0

problem on ages [#permalink]  05 Jul 2010, 18:49
five years ago,Beth's age was three times that of Amy.Ten years ago ,Beth's age was one half that of Chelsea.If "C" represents Chelsea's current age ,which of the following represents Amy's current age?

A)(c/6)+5
B)2c
C)(c-10)/3
D)3c-5
E)(5c/3)-10
Kaplan GMAT Instructor
Joined: 21 Jun 2010
Posts: 75
Location: Toronto
Followers: 24

Kudos [?]: 131 [0], given: 2

Re: problem on ages [#permalink]  05 Jul 2010, 19:27
Hi,

we have to translate the English into algebraic expressions that reflect the same meaning.

Quote:
five years ago,Beth's age was three times that of Amy.

How old is Beth today?...Let's call it "B"

Then, how old was Beth five years ago?..."B-5"

Similarly, how old was Amy five years ago?..."A-5"

At this point in time, Beth's age was three times that of Amy. So:

B-5 = 3*(A-5) (1)

Similarly, this sentence:

Quote:
Ten years ago ,Beth's age was one half that of Chelsea.

yields:

B-10 = (C-10)/2 (2)

We want to solve for A in terms of C. So, we want to get rid of B. The easiest way is to equate the two equations. But the left-hand sides of each equation are different. So, just subtract 5 from both sides of (1) (OR add 5 to both sides of (2)):

B-5 -5 = 3*(A-5) - 5
B-10 = 3*(A-5) -5

Because B-10 = B-10, we have:

3*(A-5) - 5 = (C-10)/2

Solving for A, we have:

A = C/6 + 5

Choose A!
Manager
Joined: 22 Oct 2009
Posts: 242
GMAT 1: 760 Q49 V44
GPA: 3.88
Followers: 6

Kudos [?]: 75 [0], given: 1

Re: problem on ages [#permalink]  05 Jul 2010, 19:35

The solution I got is equivalent to answer A.
Kaplan GMAT Instructor
Joined: 21 Jun 2010
Posts: 75
Location: Toronto
Followers: 24

Kudos [?]: 131 [0], given: 2

Re: problem on ages [#permalink]  05 Jul 2010, 20:14
Hi dinesh,

did you double post this? Seems there's two threads on this same topic started by the same OP at teh same time! Anyways, I've just copied and pasted the explanation I gave in the other thread. Hope it helps!

we have to translate the English into algebraic expressions that reflect the same meaning.

Quote:
five years ago,Beth's age was three times that of Amy
.

How old is Beth today?...Let's call it "B"

Then, how old was Beth five years ago?..."B-5"

Similarly, how old was Amy five years ago?..."A-5"

At this point in time, Beth's age was three times that of Amy. So:

B-5 = 3*(A-5) (1)

Similarly, this sentence:

Quote:
Ten years ago ,Beth's age was one half that of Chelsea.

yields:

B-10 = (C-10)/2 (2)

We want to solve for A in terms of C. So, we want to get rid of B. The easiest way is to equate the two equations. But the left-hand sides of each equation are different. So, just subtract 5 from both sides of (1) (OR add 5 to both sides of (2)):

B-5 -5 = 3*(A-5) - 5
B-10 = 3*(A-5) -5

Because B-10 = B-10, we have:

3*(A-5) - 5 = (C-10)/2

Solving for A, we have:

A = C/6 + 5

Choose A!
Intern
Joined: 11 May 2010
Posts: 32
Followers: 1

Kudos [?]: 7 [0], given: 13

Re: problem on ages [#permalink]  06 Jul 2010, 05:47
I started with Chelsey. Her age 10 years ago was C-10, so Beth's age 10 years ago was (c-10)/2. Next stage: Beth's age 5 years ago was (c-10)/2+5, and Amy's age 5 years ago was ((c-10)/2+5)/3. Now: Amy's age is ((c-10)/2+5)/3+5.
Now we should simplify the algebraic expression:
((c-10)/2+10/2)/3+5=c/6+5
Re: problem on ages   [#permalink] 06 Jul 2010, 05:47
Similar topics Replies Last post
Similar
Topics:
6 When a person aged 39 is added to a group of n people, the average age 6 19 Aug 2015, 01:03
3 Two digits in hunter's age are the same as the digit in the titan's ag 2 02 Feb 2015, 04:09
Liam's age is 5 years more than twice Gita's age 2 01 Jan 2014, 07:46
1 The sum of Abbie's age and Iris's age is 42 years. 11 years 3 01 Jan 2014, 07:42
A math problem,s 2 07 Aug 2011, 04:02
Display posts from previous: Sort by