Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 563 reviewsTarget Test Prep

Ages of Ebo and Atu

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 11
Joined: Sun May 24, 2015 9:17 pm
by Pazoki » Fri Jul 22, 2016 4:03 pm
Below is a question by GMAT Prep Now.

5 years ago, Ebo was 3 times as old as Atu. In 3 years Ebo will be twice as old as Atu. What is the sum of their ages now?

A) 18
B) 24
C) 28
D) 35
E) 42

Brent solved it based on 2 variable and 2 equations. I solved it with on variable but not sure my way is valid or not. thank for any hint or guidance.

I got Aut as he/she is younger. So Ebo in 5 yaers ago is 3(A-5) and when we add 8 years to it we will get 3 years from now which will be 3(A-5)+8=2(A+3) ==> 3A-7=2(A+3),solved for "A" and got A=13, then plug "A" in in the equation to solve for Ebo or E=29 then E+A=> 29+13=42 (E) is correct.
Did I do correctly?
Top
Join the discussion
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
Elite Legendary Member
Posts: 10391
Joined: Sun Jun 23, 2013 6:38 pmFollowed by: 511 members
Location: Palo Alto, CA
Thanked: 2867 times
GMAT Score:800

by [email protected] » Fri Jul 22, 2016 6:12 pm
Hi Pazoki,

Yes, your approach is correct. You're going to find that most GMAT questions can be solved in a variety of ways (and there are even various ways of 'doing math' that will get you to the correct answer). Ultimately, you should be honing all of your skills so that you can choose whichever approach is fastest and easiest for you on Test Day (instead of ending up 'stuck' with just one approach because you didn't practice the others).

Relative to using two variables, was this approach easier? Was it faster? Did you have to go back and reread the prompt repeatedly while you were working through your calculations? These are relevant questions to consider. Getting the correct answer is important, but doing so in an efficient fashion is also important.

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Top
Join the discussion
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members
Location: New York, NY
Thanked: 13060 times
GMAT Score:790

by GMATGuruNY » Sun Jul 24, 2016 4:03 pm
5 years ago, Ebo was 3 times as old as Atu. In 3 years, Ebo will be twice as old as Atu. What is the sum of their ages now?

A) 18
B) 24
C) 28
D) 35
E) 42
An alternate approach is to TEST CASES.

5 years ago, Ebo was 3 times as old as Atu.
What is the sum of their ages now?

Case 1: Five years ago A=1 and E = 3*1 = 3
Sum of the their ages now = (1+5) + (3+5) = 14.
14 is not among the answer choices.

Case 2: Five years ago A=2 and E = 3*2 = 6
Sum of the their ages now = (2+5) + (6+5) = 18.
In 3 years, A = 7+3 = 10 and E = 11+3 = 14.
Since Ebo is not twice as old as Atu, eliminate A.

Case 3: Five years ago A=3 and E = 3*3 = 9
Sum of the their ages now = (3+5) + (9+5) = 22.
22 is not among the answer choices.

Notice the PATTERN:
The resulting sums -- 14, 18, 22 -- keep increasing by 4.
Thus, the correct sum must be in the following list:
14, 18, 22, 26, 30, 34, 38, 42...

Only the value in red is among the remaining answer choices.

The correct answer is E.
Last edited by GMATGuruNY on Sun Jul 24, 2016 7:46 pm, edited 1 time in total.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top
Join the discussion
Junior | Next Rank: 30 Posts
Posts: 11
Joined: Sun May 24, 2015 9:17 pm

by Pazoki » Sun Jul 24, 2016 7:36 pm
GMATGuruNY wrote:
5 years ago, Ebo was 3 times as old as Atu. In 3 years, Ebo will be twice as old as Atu. What is the sum of their ages now?

A) 18
B) 24
C) 28
D) 35
E) 42
Thanks Mitch for the reply.
as you mentioned in case 2:

Case 2: Five years ago A=2 and E = 3*2 = 6
Sum of the their ages now = (2+5) + (6+5) = 18.
18 is not among the answer choices.

But 18 is among the answer choices as first answer choice is A)18

so how can we choose between A)18 and E)42?

Thanks
Top
Join the discussion
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members
Location: New York, NY
Thanked: 13060 times
GMAT Score:790

by GMATGuruNY » Sun Jul 24, 2016 7:51 pm
Pazoki wrote:Thanks Mitch for the reply.
as you mentioned in case 2:

Case 2: Five years ago A=2 and E = 3*2 = 6
Sum of the their ages now = (2+5) + (6+5) = 18.
18 is not among the answer choices.

But 18 is among the answer choices as first answer choice is A)18
Good catch.
I've edited my post accordingly.
so how can we choose between A)18 and E)42?

Thanks
In the edited post, I explain how to eliminate A.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top
Join the discussion

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16206
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

by Brent@GMATPrepNow » Mon Jul 25, 2016 2:39 pm
Pazoki wrote:Below is a question by GMAT Prep Now.

5 years ago, Ebo was 3 times as old as Atu. In 3 years Ebo will be twice as old as Atu. What is the sum of their ages now?

A) 18
B) 24
C) 28
D) 35
E) 42
Here's the video solution that Pazoki noted: https://www.gmatprepnow.com/module/gmat ... /video/909

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
GMAT Instructor
Posts: 2629
Joined: Wed Sep 12, 2012 3:32 pmFollowed by: 119 members
Location: East Bay all the way
Thanked: 625 times
GMAT Score:780

by Matt@VeritasPrep » Thu Aug 04, 2016 9:55 pm
Pazoki wrote: I got Aut as he/she is younger. So Ebo in 5 yaers ago is 3(A-5) and when we add 8 years to it we will get 3 years from now which will be 3(A-5)+8=2(A+3) ==> 3A-7=2(A+3),solved for "A" and got A=13, then plug "A" in in the equation to solve for Ebo or E=29 then E+A=> 29+13=42 (E) is correct.
Did I do correctly?
This is great! Be careful on test day, though: it's easy to lose track of what you're doing by trying to cut out the other variable. It might be safer just to say

3*(A - 5) = (E - 5)

and

2*(A + 3) = (E + 3)

From there, manipulate each equation so they each equal the same thing (E):

3*(A - 5) + 5 = E
2*(A + 3) - 3 = E

Then set the two left sides equal

3 * (A - 5) + 5 = 2 * (A + 3) - 3

to find Atu's age, from which it's easy to also find Ebo's age.
Top
Join the discussion