City X has a population 4 times as great as the population of City Y, which has a population twice as great as the population of City Z. What is the ratio of the population of City X to the population of City Z?
A) 1:8
B) 1:4
C) 2:1
D) 4:1
E) 8:1
E
OG City X has a population 4 times
This topic has expert replies
-
- Master | Next Rank: 500 Posts
- Posts: 394
- Joined: Sun Jul 02, 2017 10:59 am
- Thanked: 1 times
- Followed by:5 members
GMAT/MBA Expert
- Brent@GMATPrepNow
- 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
One approach is to assign some values that meet the given informationAbeNeedsAnswers wrote:City X has a population 4 times as great as the population of City Y, which has a population twice as great as the population of City Z. What is the ratio of the population of City X to the population of City Z?
A) 1:8
B) 1:4
C) 2:1
D) 4:1
E) 8:1
City Y has a population twice as great as the population of City Z
Let's say the population of City Z is 1 person
This means the population of City Y is 2 people
City X has a population 4 times as great as the population of City Y
If the population of City Y is 2 people, then the population of City X is 8 people
So, the ratio of the population of City X to the population of City Z = 8 to 1
Answer: E
Cheers,
Brent
GMAT/MBA Expert
- Scott@TargetTestPrep
- GMAT Instructor
- Posts: 7242
- Joined: Sat Apr 25, 2015 10:56 am
- Location: Los Angeles, CA
- Thanked: 43 times
- Followed by:29 members
We are given that City X has a population 4 times as great as the population of City Y and that City Y has a population twice as great as the population of City Z.AbeNeedsAnswers wrote:City X has a population 4 times as great as the population of City Y, which has a population twice as great as the population of City Z. What is the ratio of the population of City X to the population of City Z?
A) 1:8
B) 1:4
C) 2:1
D) 4:1
E) 8:1
If we let the population of City X = x, the population of city Y = y, and the population of city Z = z, we can create the following equations:
x = 4y
and
y = 2z
We need to determine the ratio of the population of City X to the population of City Z, or x/z. We see that:
x = 4y
x = 4(2z)
z = 8z
x/z = 8
Thus, the ratio is 8 : 1.
Answer: E
Scott Woodbury-Stewart
Founder and CEO
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews
GMAT/MBA Expert
- [email protected]
- Elite Legendary Member
- Posts: 10392
- Joined: Sun Jun 23, 2013 6:38 pm
- Location: Palo Alto, CA
- Thanked: 2867 times
- Followed by:511 members
- GMAT Score:800
Hi All,
We're told that City X has a population 4 TIMES as great as the population of City Y, which has a population TWICE as great as the population of City Z. We're asked for the ratio of the population of City X to the population of City Z. Based on the design of this question - and the design of the answer choices, we can get the correct answer without doing much math at all.
To start, we know that the population of City X is 4 TIMES as great as that of City Y and City Y's population is GREATER than that of City Z. When comparing City X's population to City Z's, we know that City X's population has to be MORE than 4 TIMES greater than City Z's... and there's only one answer that would account for that type of difference..
Final Answer: E
GMAT assassins aren't born, they're made,
Rich
We're told that City X has a population 4 TIMES as great as the population of City Y, which has a population TWICE as great as the population of City Z. We're asked for the ratio of the population of City X to the population of City Z. Based on the design of this question - and the design of the answer choices, we can get the correct answer without doing much math at all.
To start, we know that the population of City X is 4 TIMES as great as that of City Y and City Y's population is GREATER than that of City Z. When comparing City X's population to City Z's, we know that City X's population has to be MORE than 4 TIMES greater than City Z's... and there's only one answer that would account for that type of difference..
Final Answer: E
GMAT assassins aren't born, they're made,
Rich