2k years ago Frank was 3k years old. In k years Frank's age,

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Magoosh

2k years ago Frank was 3k years old. In k years Frank's age, in years, will be

A. 4k
B. 5k
C. 6k
D. 7k
E. 8k

OA C.

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by GMATGuruNY » Fri Dec 07, 2018 5:29 am
AAPL wrote:Magoosh

2k years ago Frank was 3k years old. In k years Frank's age, in years, will be

A. 4k
B. 5k
C. 6k
D. 7k
E. 8k
Let k=10.

2k years ago Frank was 3k years old.
Since k=10, 20 years ago Frank was 30 years old, implying that his age now = 30+20 = 50.

In k years Frank's age, in years, will be:
Since Frank is now 50 years old, Frank's age in 10 years = 50+10 = 60.

The correct answer must yield a value of 60 when k=10.
Only C works:
6k = 6*10 = 60.

The correct answer is C.
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by Brent@GMATPrepNow » Fri Dec 07, 2018 6:08 am
AAPL wrote:2k years ago Frank was 3k years old. In k years Frank's age, in years, will be
A. 4k
B. 5k
C. 6k
D. 7k
E. 8k
These kinds of questions (Variables in the Answer Choices - VIACs) can be answered algebraically or using the input-output approach.
Mitch has solved the question using the input-output approach, so let's use the algebraic approach.

2k years ago Frank was 3k years old.
We're given Frank's age 2k YEARS AGO.
So, Frank's PRESENT age = 3k + 2k = 5k

In k years Frank's age, in years, will be
In k years, Frank will be k years older than his CURRENT age.
So, IN k YEARS, Frank's age will equal 5k + k = 6k

Answer: C

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by Scott@TargetTestPrep » Thu Mar 21, 2019 4:45 pm
AAPL wrote:Magoosh

2k years ago Frank was 3k years old. In k years Frank's age, in years, will be

A. 4k
B. 5k
C. 6k
D. 7k
E. 8k

OA C.
Let F = Frank's age now. So we have:

F- 2k = 3k

F = 5k

Therefore, in k years, Frank will be F + k = 5k + k = 6k years old.

Answer: C

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