BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Brent is 18 years younger than Justin. If in 5 years Brent will be half as old as Justin, how old was Justin 5 years ago

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 2898
Joined: Thu Sep 07, 2017 2:49 pm
Thanked: 6 times
Followed by:5 members

Brent is 18 years younger than Justin. If in 5 years Brent will be half as old as Justin, how old was Justin 5 years ago

by Vincen » Wed Jan 12, 2022 9:32 am

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

Brent is 18 years younger than Justin. If in 5 years Brent will be half as old as Justin, how old was Justin 5 years ago?

A. 8
B. 18
C. 21
D. 26
E. 31

Answer: D

Source: Veritas Prep
Top
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

Re: Brent is 18 years younger than Justin. If in 5 years Brent will be half as old as Justin, how old was Justin 5 years

by Brent@GMATPrepNow » Wed Jan 12, 2022 10:33 am
Vincen wrote: ↑
Wed Jan 12, 2022 9:32 am
 Brent is 18 years younger than Justin. If in 5 years Brent will be half as old as Justin, how old was Justin 5 years ago?

A. 8
B. 18
C. 21
D. 26
E. 31

Answer: D

Source: Veritas Prep
Brent is 18 years younger than Justin.
Let J = Justin's PRESET AGE
So, J-18 = Brent's PRESENT age

In 5 years, both people will be 5 years older
So, J + 5 = Justin's AGE IN 5 YEARS
And (J-18) + 5 = Brent's AGE IN 5 YEARS
Simplify to get: J - 13 = Brent's AGE IN 5 YEARS

In 5 years Brent will be half as old as Justin.
In other words, IN 5 YEARS 5 years, (Brent's age) = (1/2)(Justin's age)
We can write: J - 13 = (1/2)(J + 5)
Multiply both sides by 2 to get: 2J - 26 = J + 5
Solve to get: J = 31
So, Justin's PRESENT age = 31

How old was Justin 5 years ago?
Justin's age 5 years ago = 31 - 5 = 26

Answer: D
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Post new topic Post Reply
• Page 1 of 1