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­First two containers: 64%
Third Container: 58%
 
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Bunuel
Humidity percentage is the water vapor mass contained within the total mass of air inside a specified volume of air. An observatory has three large containers each containing 100 tons of compressed air. The first two containers have the same humidity percentage. In an experiment, the air from all three containers was mixed into a container that had practically no air before the experiment. The humidity percentage of the combined air was found to be 62%.

In the table, select a humidity percentage for the First two containers and a humidity percentage for the Third container that are jointly consistent with the given information. Make only two selections, one in each column.


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We essentially have a 300ton (100+100+100) container with 62% water vapor mass, i.e 186 tons of water vapor mass. Let us check ­each possible option for the concentration percentage of compressed air in the first two containers:
58%: 116 tons combined in the first two containers; 186-116= 70 tons left, no option for 72% humidity percentage in the third container provided
59%: 118 tons combined in the first two containers; 186-118= 68 tons left, no option for 68% humidity percentage in the third container provided
60%: 120 tons combined in the first two containers; 186-120= 66 tons left, no option for 66% humidity percentage in the third container provided
64%: 128 tons combined in the first two containers; 186-128= 58 tons left, option 1, 58% for humidity percentage in the third container provided
65%: 130 tons combined in the first two containers; 186-130= 56 tons left, no option for 56% humidity percentage in the third container provided

Thus 64% humidity in the first two, and 58% in the third is the only viable combination
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Make eq:

((2x % for first two) +x)/3 = 62%

Only correct: (64+64)+x=186 where x = 58
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Let's denote the humidity percentage of the first two containers as x and the third container as y with each container having a total mass M. When mixed together, the total mass of the combined mix is 3M and the total water content is the sum of the contributions from each container:
Each one of the first two containers contributes \(x*M\)
The third container contributes \(y*M\)

The humidity percentage of the resulting mixture can be calculated as follows:

\(\frac{x*M + x*M + y*M}{3M} = \frac{2}{3}*x+\frac{1}{3}*y = 62\%\)

Let's replace the values of x and y in the equation from the table above to find the right answer.
The only combination that satisfies the equation is \(x=64\%\) and \( y=58\%\) and is the right answer.
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Bunuel
Humidity percentage is the water vapor mass contained within the total mass of air inside a specified volume of air. An observatory has three large containers each containing 100 tons of compressed air. The first two containers have the same humidity percentage. In an experiment, the air from all three containers was mixed into a container that had practically no air before the experiment. The humidity percentage of the combined air was found to be 62%.

In the table, select a humidity percentage for the First two containers and a humidity percentage for the Third container that are jointly consistent with the given information. Make only two selections, one in each column.


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­
Humidity % of two containers are the same. Each container has 100 tons of compressed air. So two containers with same humidity of x% has 2x of humidity in total
Let third container has y% of humidity 
so 2x+ y= 62%*300
2x+y=186
if x=64 , 128+y=186
so y= 58

Hence 1st two containers have 64% humidity and third container has 58% humidity
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First two container - 64%
Third = 58%


2x+y= 0.62(300)
2x+y=186

Solving between the option Only this fits so
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vpm = water vapor mass of container 1
vpm2= water vapor mass of container 2
x = water vapor mass of container 3

vpm+vpm2+x= .62*(100+100+100)=.62*300=186

vpm=vpm2= y

2y+x=186
even+even=Even
x must be even
so option for x=58,60,64

lets try

y=(186-x)/2
y=93+ (x/2)

x=64 y=61 no in the options
x=60 y= 63 no in the options
x=64 y=58 in the options

First two containers
58
Third container
64
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62 is the average of the three containers.

(2x+y)/3 = 62
2x+y = 186

from trial and error:
Option 1: 58
186- 2(58) = 70. 70 is not an option.
186 - 58 = 128. 128/2 = 64. 64 is an option.
2x = 64, y = 58.­
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­Humidity in Container 1 = Humidity in Container 2 = x
Humidity in Container 3 = y

(2x+y)/3 = 62
2x + y = 186

The only solution would be if x = 64 and y = 58
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­Let a be the amount of mass of water in container 1 and 2, and b the amount of mass of water in the third container.
We construct the following equation
(2a + b)/300 = 62/100
By subtracting.
2a + b = 186
Trying all the available options we find that a = 64 and b = 58.
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Humidity percentage is the water vapor mass contained within the total mass of air inside a specified volume of air. An observatory has three large containers each containing 100 tons of compressed air. The first two containers have the same humidity percentage. In an experiment, the air from all three containers was mixed into a container that had practically no air before the experiment. The humidity percentage of the combined air was found to be 62%.

In the table, select a humidity percentage for the <i>First two containers</i> and a humidity percentage for the <i>Third container</i> that are jointly consistent with the given information. Make only two selections, one in each column.

The air from the 3 containers is being mixed, so this is a case of mixtures.

Given
Vol of air in the two containers with the same humidity = 200 tons<br />
Vol of air in the 3rd container = 100 tons<br />
The final mixture has a volume of 62%<br />

62% of 300 tons = \(\text{x% of 200 tons+y% of 100 tons}\)­

186 = 2x + y

Try values for x and match y from this equation,
For x = 64, y = 58 - matches the answer

 
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­Please find the answer to the question attached. ­
Attachments

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Humidity percentage is the water vapor mass contained within the total mass of air inside a specified volume of air. An observatory has three large containers each containing 100 tons of compressed air. The first two containers have the same humidity percentage. In an experiment, the air from all three containers was mixed into a container that had practically no air before the experiment. The humidity percentage of the combined air was found to be 62%.

Lets say vapor mass in firs two contains A and B is x% each and third container is y%. Since each container is 100 tons vapor mass in A, B, C is x, x and y ton respectively.
Total percentage would be [(2x+y)/300] * 100 = 62 i.e. 2x+y = 62*3 i.e. 2x + y = 186.

Using options given:
x= 58 -> y = 70
x= 59 -> y = 68
x= 60 -> y = 66
x = 64 -> y = 58 - which works
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Let humidity % of Container A and B be x% each
and for Container C be y%

as per the statement,
x% (100) + x% (100) + y% (100) = 62% (100+100+100)
2x + y = 186

Plugging in numbers from the table,
x=64
y=58
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Quote:
 
­
Humidity percentage is the water vapor mass contained within the total mass of air inside a specified volume of air. An observatory has three large containers each containing 100 tons of compressed air. The first two containers have the same humidity percentage. In an experiment, the air from all three containers was mixed into a container that had practically no air before the experiment. The humidity percentage of the combined air was found to be 62%.

In the table, select a humidity percentage for the First two containers and a humidity percentage for the Third container that are jointly consistent with the given information. Make only two selections, one in each column.

total net is 300
62 % of 300 is 186 
A + B + C = 186
since A = B
2A + C = 186
for first two containers humidity be 64 % each so third will be 58%First two containers 64 %;
Third container
58%
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­we could use the balance method, for which we needed to see which pair of number gave us the 62%.
It was 60% for the two containers and 64% for the third. Using the method, with the first 2 we were 4 point below the average, so the third had to make up for 4 points.
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­The easiest way to find the answer is to caluclate differences between each value and the avg '62'58%  -4%      59%  -3% 60%  -2%64%  +2%65%  +3%It's easy to see how adding 2 64% containers to 1 58% container gives us an avg of 62%. 
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