THE RATIO OF TWO QUANTITIES IS 3 TO 4. IF EACH OF THE QUANTITIES IS INCREASED BY 5, WHAT IS THE RATIO OF THESE TWO NEW QUANTITIES?
A. 3/4
B. 8/9
C. 18/19
D. 23/24
E. IT CANNOT BE DETERMINED FROM THE INFORMATION GIVEN
5-Day Free Trial
5-day free, full-access trial TTP
Available with Beat the GMAT members only code
MORE DETAILS
RATIO OF TWO QUANTITIES
This topic has expert replies
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
Test two cases and see what happens.oquiella wrote:THE RATIO OF TWO QUANTITIES IS 3 TO 4. IF EACH OF THE QUANTITIES IS INCREASED BY 5, WHAT IS THE RATIO OF THESE TWO NEW QUANTITIES?
A. 3/4
B. 8/9
C. 18/19
D. 23/24
E. IT CANNOT BE DETERMINED FROM THE INFORMATION GIVEN
case 1: x = 3 and y = 4, so the ratio x/y = 3/4
Now add 5 to both quantities to get:
x = 8 and y = 9, so the NEW ratio = 8/9
case 2: x = 6 and y = 8, so the ratio x/y = 6/8 = 3/4
Now add 5 to both quantities to get:
x = 11 and y = 13, so the NEW ratio = 11/13
Answer: E
Brent Hanneson - Creator of GMATPrepNow.com
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 oquiella,
When dealing with a starting ratio, it's important to remember that the ratio does NOT actually tell you how many "items" you're dealing with. Here, we're given a starting ratio of 3 to 4, but we don't know the exact number of each item - we just know how they relate to one another (for every 3 we have of the first, we have 4 of the second).
Thus, the actual values are limitless...
3 and 4
6 and 8
9 and 12
12 and 16
Etc.
As Brent showed in his explanation, adding 5 to both values does NOT yield a consistent result, so the ending ratio cannot be determined (which is to say that it can have more than one possible value).
Final Answer: E
GMAT assassins aren't born, they're made,
Rich
When dealing with a starting ratio, it's important to remember that the ratio does NOT actually tell you how many "items" you're dealing with. Here, we're given a starting ratio of 3 to 4, but we don't know the exact number of each item - we just know how they relate to one another (for every 3 we have of the first, we have 4 of the second).
Thus, the actual values are limitless...
3 and 4
6 and 8
9 and 12
12 and 16
Etc.
As Brent showed in his explanation, adding 5 to both values does NOT yield a consistent result, so the ending ratio cannot be determined (which is to say that it can have more than one possible value).
Final Answer: E
GMAT assassins aren't born, they're made,
Rich
-
Max@Math Revolution
- Elite Legendary Member
- Posts: 3991
- Joined: Fri Jul 24, 2015 2:28 am
- Location: Las Vegas, USA
- Thanked: 19 times
- Followed by:37 members
Forget conventional ways of solving math questions. In PS, IVY approach is the easiest and quickest way to find the answer.
THE RATIO OF TWO QUANTITIES IS 3 TO 4. IF EACH OF THE QUANTITIES IS INCREASED BY 5, WHAT IS THE RATIO OF THESE TWO NEW QUANTITIES?
A. 3/4
B. 8/9
C. 18/19
D. 23/24
E. IT CANNOT BE DETERMINED FROM THE INFORMATION GIVEN
Let the two quantities be a and b. Then we have a/b= 3/4, that means 4a=3b. We can put a=3k and b=4k. We should find the ratio (a+5)/(b+5)=(3k+5)/(4k+5). That means, however, (3k+5)/(4k+5) has different value depending on the value of k. So we cannot determine the ratio of (a+5) to (b+5) with only information above. The answer is, therefore, E)
Math Revolution : Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World's First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Unlimited Access to over 120 free video lessons - try it yourself (https://www.mathrevolution.com/gmat/lesson)
See our Youtube demo (https://www.youtube.com/watch?v=R_Fki3_2vO8)
THE RATIO OF TWO QUANTITIES IS 3 TO 4. IF EACH OF THE QUANTITIES IS INCREASED BY 5, WHAT IS THE RATIO OF THESE TWO NEW QUANTITIES?
A. 3/4
B. 8/9
C. 18/19
D. 23/24
E. IT CANNOT BE DETERMINED FROM THE INFORMATION GIVEN
Let the two quantities be a and b. Then we have a/b= 3/4, that means 4a=3b. We can put a=3k and b=4k. We should find the ratio (a+5)/(b+5)=(3k+5)/(4k+5). That means, however, (3k+5)/(4k+5) has different value depending on the value of k. So we cannot determine the ratio of (a+5) to (b+5) with only information above. The answer is, therefore, E)
Math Revolution : Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World's First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Unlimited Access to over 120 free video lessons - try it yourself (https://www.mathrevolution.com/gmat/lesson)
See our Youtube demo (https://www.youtube.com/watch?v=R_Fki3_2vO8)
GMAT/MBA Expert
-
Scott@TargetTestPrep
- GMAT Instructor
- Posts: 7249
- Joined: Sat Apr 25, 2015 10:56 am
- Location: Los Angeles, CA
- Thanked: 43 times
- Followed by:29 members
We are given that the ratio of two quantities is 3 to 4 or 3x to 4x. When each quantity is increased by 5, we have:oquiella wrote:The ratio of two quantities is 3 to 4. If each of the quantities is increased by 5, what is the ratio of these two new quantities?
A. 3/4
B. 8/9
C. 18/19
D. 23/24
E. It cannot be determined from the information given.
(3x + 5)/(4x + 5)
We see that this is not enough information to determine a new ratio.
For instance, if x = 1, then (3x + 5)/(4x + 5) = 8/9; however, if x = 2, then (3x + 5)/(4x + 5) = 11/13.
Since 8/9 does not equal 11/13, we cannot determine a unique value of the new ratio.
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
