the three containers

This topic has expert replies
User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

the three containers

by sanju09 » Wed Sep 16, 2015 11:09 pm
Container A and Container B are initially full of water and the volumes of Container A and Container B are in the ratio 2 to 3 respectively. A third container, Container C, which is in volume the largest among the three containers, is initially 20 percent full of water. When one-half of Container A's water and one-third of Container B's water is poured into Container C, it's now 40 percent full of water. What is the ratio in the volumes of the three containers A, B, and C respectively?
A. 1 to 2 to 4
B. 2 to 3 to 2
C. 2 to 3 to 5
D. 2 to 3 to 8
E. 2 to 3 to 10


Made Up!
Last edited by sanju09 on Fri Sep 18, 2015 2:23 am, edited 1 time in total.
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Source: — Problem Solving |

User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 am
Location: Las Vegas, USA
Thanked: 19 times
Followed by:37 members

by Max@Math Revolution » Thu Sep 17, 2015 12:41 am
Forget conventional ways of solving math questions. In PS, IVY approach is the easiest and quickest way to find the answer.


Container A and Container B are initially full of water and the volumes of Container A and Container B are in the ratio 2 to 3 respectively. A third container, Container C, which is in volume the largest among the three containers, is initially 20 percent full of water. When one-half of Container A's water and one-third of Container B's water is poured into Container C, it's now 40 percent full of water. What is the ratio in the original volumes of the three containers A, B, and C respectively?
A. 1 to 2 to 4
B. 2 to 3 to 2
C. 2 to 3 to 5
D. 2 to 3 to 8
E. 2 to 3 to 10



Since the ratio of the volumes of Container A and Container B is 2 to 3, we can let the volumes of Container A be 2T and that of Container B be 3T. Now since one-half of Container A's water(=1/2 * 2T= T) and one-third of Container B's water(=1/3 * 3T = T) is poured into Container C, the total water poured into Container C is 2T. It is 20% of the Container C since it has at the beginning 20% of water and it increases to the 40% by pouring 2T of water. The original volumes of the Container C is, therefore, 10T(?:2T=100:20 ---> ?=5*2T). The ratio in the original volumes of the three containers A, B, and C is 2T : 3T : 10T = 2:3:10. So the answer is 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)

User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Thu Sep 17, 2015 2:57 am
sanju09 wrote:Container A and Container B are initially full of water and the volumes of Container A and Container B are in the ratio 2 to 3 respectively. A third container, Container C, which is in volume the largest among the three containers, is initially 20 percent full of water. When one-half of Container A's water and one-third of Container B's water is poured into Container C, it's now 40 percent full of water. What is the ratio in the original volumes of the three containers A, B, and C respectively?
A. 1 to 2 to 4
B. 2 to 3 to 2
C. 2 to 3 to 5
D. 2 to 3 to 8
E. 2 to 3 to 10
The intended meaning of the phrase in red is unclear.
The phrase original volumes suggests values that can CHANGE from ORIGINAL values to NEW values: in other words, the AMOUNTS OF WATER in the three containers.
The phrase volumes of the three containers seems to refer to the CAPACITY of each container: how much water each container can hold.
The solution below presumes that the question stem is asking for the following ratio:
(capacity of A) : (capacity of B) : (capacity of C).

We can PLUG IN THE ANSWERS, which represent the ratio of the three capacities.
At the start, A is 100% full, B is 100% full, and C is 20% full.
When 1/2 of A and 1/3 of B are poured into C, the percentage of water in C increases from 20% to 40%.
In other words, the amount of water in C must DOUBLE.

Answer choice D:
Let A = 20 liters of water, B = 30 liters of water and C = 20% of 80 = 16 liters of water.
(1/2 of A) + (1/3 of B) = 10 + 10 = 20.
Since the value in red (20) will more than double the amount of water in C (16), the relative capacity of C is too small.
Eliminate D.

Answer choice E:
Let A = 20 liters of water, B = 30 liters of water and C = 20% of 100 = 20 liters of water.
(1/2 of A) + (1/3 of B) = 10 + 10 = 20.
Success!
The value in red (20) will double the amount of water in C (20).

The correct answer is E.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

User avatar
GMAT Instructor
Posts: 3650
Joined: Wed Jan 21, 2009 4:27 am
Location: India
Thanked: 267 times
Followed by:80 members
GMAT Score:760

by sanju09 » Fri Sep 18, 2015 2:26 am
GMATGuruNY wrote:
sanju09 wrote:Container A and Container B are initially full of water and the volumes of Container A and Container B are in the ratio 2 to 3 respectively. A third container, Container C, which is in volume the largest among the three containers, is initially 20 percent full of water. When one-half of Container A's water and one-third of Container B's water is poured into Container C, it's now 40 percent full of water. What is the ratio in the original volumes of the three containers A, B, and C respectively?
A. 1 to 2 to 4
B. 2 to 3 to 2
C. 2 to 3 to 5
D. 2 to 3 to 8
E. 2 to 3 to 10
The intended meaning of the phrase in red is unclear.
The phrase original volumes suggests values that can CHANGE from ORIGINAL values to NEW values: in other words, the AMOUNTS OF WATER in the three containers.
The phrase volumes of the three containers seems to refer to the CAPACITY of each container: how much water each container can hold.
The solution below presumes that the question stem is asking for the following ratio:
(capacity of A) : (capacity of B) : (capacity of C).

We can PLUG IN THE ANSWERS, which represent the ratio of the three capacities.
At the start, A is 100% full, B is 100% full, and C is 20% full.
When 1/2 of A and 1/3 of B are poured into C, the percentage of water in C increases from 20% to 40%.
In other words, the amount of water in C must DOUBLE.

Answer choice D:
Let A = 20 liters of water, B = 30 liters of water and C = 20% of 80 = 16 liters of water.
(1/2 of A) + (1/3 of B) = 10 + 10 = 20.
Since the value in red (20) will more than double the amount of water in C (16), the relative capacity of C is too small.
Eliminate D.

Answer choice E:
Let A = 20 liters of water, B = 30 liters of water and C = 20% of 100 = 20 liters of water.
(1/2 of A) + (1/3 of B) = 10 + 10 = 20.
Success!
The value in red (20) will double the amount of water in C (20).

The correct answer is E.
The term 'original' used here may be redundant but leads to no confusion or presumption at all because ultimately it talks about the volume of the three containers, and not about the volumes of water they currently hold. But still, since I too feel it useless, hence it's removed now. Thanks Mitch.
The mind is everything. What you think you become. -Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com