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17 Jan 2016, 10:21
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C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
81% (01:26) correct
19%
(01:55)
wrong
based on 69
sessions
History
Date
Time
Result
Not Attempted Yet
Macey is three times as old as Mike. In eight years, she will be twice as old as Mike. How old was Macey three years ago?
A. 5
B. 8
C. 21
D. 24
E. 30
A. 5
B. 8
C. 21
D. 24
E. 30
FacelessMan
Joined: 19 Dec 2015
Last visit: 17 Jul 2020
Posts: 86
Own Kudos:
Given Kudos: 13
Location: United States
Schools: Duke '19 Kenan-Flagler '19
GMAT 1: 720 Q50 V38
GPA: 3.8
WE:Information Technology (Computer Software)
17 Jan 2016, 10:28
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Let's Macey's present age be x, and Mike's present age be y. Now lets formulate equations based on the given information.
1. x = 3y
2. (x+8)=2(y+8) => x-2y = 8
Solving these equations, we get x= 24, and y = 8.
Macey's age 3 years ago = 24 - 3 = 21. Hence C.
1. x = 3y
2. (x+8)=2(y+8) => x-2y = 8
Solving these equations, we get x= 24, and y = 8.
Macey's age 3 years ago = 24 - 3 = 21. Hence C.
18 Jan 2016, 12:26
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Hi All,
This question can be solved by TESTing THE ANSWERS.
We're told that Macey is THREE TIMES as old as Mike. We're then told that, in 8 years, Macey will be TWICE as old as Mike. We're asked how old Macey was 3 YEARS AGO.
The answer choices to this question are all INTEGERS. Since Macey is NOW three times as old as Mike, her age is almost certainly going to be a multiple of 3. We're asked for her ago 3 YEARS AGO and THAT number will also be a multiple of 3 (since subtracting a multiple of 3 from another multiple of 3 will give us a multiple of 3). This is all meant to say that the correct answer is probably Answer C, D or E.
Let's TEST Answer D: 24
IF... Macey was 24 3 years ago....
Macey is now 27
Mike is now 9
In 8 years....
Macey will be 35
Mike will be 17
While that's fairly 'close' to what we're looking for, it is NOT correct (Macey is supposed to be TWICE Mike's age). Since we're close though, the correct answer is probably close to 24....
Let's TEST Answer C: 21
IF... Macey was 21 3 years ago....
Macey is now 24
Mike is now 8
In 8 years....
Macey will be 32
Mike will be 16
Since 32 is twice 16, this is a MATCH for what we were looking for, so this MUST be the correct answer.
Final Answer:
GMAT assassins aren't born, they're made,
Rich
This question can be solved by TESTing THE ANSWERS.
We're told that Macey is THREE TIMES as old as Mike. We're then told that, in 8 years, Macey will be TWICE as old as Mike. We're asked how old Macey was 3 YEARS AGO.
The answer choices to this question are all INTEGERS. Since Macey is NOW three times as old as Mike, her age is almost certainly going to be a multiple of 3. We're asked for her ago 3 YEARS AGO and THAT number will also be a multiple of 3 (since subtracting a multiple of 3 from another multiple of 3 will give us a multiple of 3). This is all meant to say that the correct answer is probably Answer C, D or E.
Let's TEST Answer D: 24
IF... Macey was 24 3 years ago....
Macey is now 27
Mike is now 9
In 8 years....
Macey will be 35
Mike will be 17
While that's fairly 'close' to what we're looking for, it is NOT correct (Macey is supposed to be TWICE Mike's age). Since we're close though, the correct answer is probably close to 24....
Let's TEST Answer C: 21
IF... Macey was 21 3 years ago....
Macey is now 24
Mike is now 8
In 8 years....
Macey will be 32
Mike will be 16
Since 32 is twice 16, this is a MATCH for what we were looking for, so this MUST be the correct answer.
Final Answer:
GMAT assassins aren't born, they're made,
Rich
