- #1

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I get stuck on this one.I'm not sure if my result is good i got 2.97 !

Please help,thank you!

- Thread starter galois
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- #1

- 8

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I get stuck on this one.I'm not sure if my result is good i got 2.97 !

Please help,thank you!

- #2

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No, your solution is not close.

How many people are there total? Answer me that first.

How many people are there total? Answer me that first.

- #3

SteamKing

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Science Advisor

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Percentage problems are like proportion problems, they just use a different way to express the proportion, with a percentage instead of a ratio.

You know the number of women in the room, but you don't know the number of men. Call the number of men 'x' and write an equation which expresses the original percentage of men to the total number of men and women. You should be able to solve this equation for the number of men. Write another equation, using the second percentage and solve it. The difference in the values of 'x' from the two equations will be the number of men asked to leave.

- #4

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There are 3 women in the room,so they make 1% of people in the room.That means there are 300 in total.No, your solution is not close.

How many people are there total? Answer me that first.

- #5

adjacent

Gold Member

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So that means there are 297 males in the room.There are 3 women in the room,so they make 1% of people in the room.That means there are 300 in total.

We know that 1% = 3, and 99-98 =1 So how many man will have to leave the room?

No need of doing many calculation here.

- #6

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3 1So that means there are 297 males in the room.

We know that 1% = 3, and 99-98 =1 So how many man will have to leave the room?

No need of doing many calculation here.

--- = --- , 300 = x

x 100

297 of them men. For the same 3 women to make up 2% of a room, there

have to be 150 people in the room,

3 2

--- = --- , 300 = 2x , 150 = x

x 100

147 of them men. 150 men have to leave the room I think.

- #7

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99:x=100:300

Percentage problems are like proportion problems, they just use a different way to express the proportion, with a percentage instead of a ratio.

You know the number of women in the room, but you don't know the number of men. Call the number of men 'x' and write an equation which expresses the original percentage of men to the total number of men and women. You should be able to solve this equation for the number of men. Write another equation, using the second percentage and solve it. The difference in the values of 'x' from the two equations will be the number of men asked to leave.

29700=100x

x=297

98:x=100:300

29400=100x

x=294

297-294=

294 is 98% of 297. Is this right ?

- #8

adjacent

Gold Member

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Yes, the answer is 3.

No 294 is 98% of 300.294 is 98% of 297. Is this right ?

- #9

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My bad,can you please write the proportions for me,i understand what SteamKing means.Yes, the answer is 3.

No 294 is 98% of 300.

- #10

adjacent

Gold Member

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This is how you do it.99:x=100:300

29700=100x

x=297

98:x=100:300

29400=100x

x=294

297-294=3

- #11

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I'm confused now.Can you please write the solution. sorry if i'm troubling you.This is how you do it.

- #12

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- #13

adjacent

Gold Member

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Now ##\frac{98}{100} \times 300= 294 ##- This means that 98% of the people is 294.

The difference between 297-294 is 3

So when 3 males get out, the percentage of males will change from 99% to 98%.

The total number of people will decrease from 300 to 297

Now, what is the other 2 percent? This made me confused too. From where did you get this question?

- #14

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Yes i get to this point to,but can't finish it i have some ideas,but I'm not sure if they are right.I got this problem from my professor to solve.

Now ##\frac{98}{100} \times 300= 294 ##- This means that 98% of the people is 294.

The difference between 297-294 is 3

So when 3 males get out, the percentage of males will change from 99% to 98%.

The total number of people will decrease from 300 to 297

Now, what is the other 2 percent? This made me confused too. From where did you get this question?

Do you think this could be the solution

3 1

--- = --- , 300 = x

x 100

297 of them men. For the same 3 women to make up 2% of a room, there

have to be 150 people in the room,

3 2

--- = --- , 300 = 2x , 150 = x

x 100

147 of them men. 150 men have to leave the room I think.

Last edited:

- #15

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Yes, the answer is 150, you have worked the problem exactly correct.

Adjacent seems to be confused here. 3 males getting out does not change the percentage to 98% because you don't have 300 people any more. 98% of 300 and 98% of some changed total are different animals.

I did it differently, but it amounts to the same thing, and I think your solution is much more clever, because while I looked at the men (which is a changing value) you looked at the women, which would not change, to solve the same problem. This was a very good thing you did.

297 / 300 = .99,

We would like to subtract an "x" from the numerator*and* denominator because men leaving decreases the number of men, 297, and the number of people, 300.

So I solved the equation:

(297-x)/(300-x) = .98

Which quickly yields x = 150.

This is how I instinctively solved it, but again, I like what you did better.

Adjacent seems to be confused here. 3 males getting out does not change the percentage to 98% because you don't have 300 people any more. 98% of 300 and 98% of some changed total are different animals.

I did it differently, but it amounts to the same thing, and I think your solution is much more clever, because while I looked at the men (which is a changing value) you looked at the women, which would not change, to solve the same problem. This was a very good thing you did.

297 / 300 = .99,

We would like to subtract an "x" from the numerator

So I solved the equation:

(297-x)/(300-x) = .98

Which quickly yields x = 150.

This is how I instinctively solved it, but again, I like what you did better.

Last edited:

- #16

adjacent

Gold Member

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I don't think so. I didn't understand his workings.Yes, the answer is 150, you have worked the problem exactly correct.

If 150 people left the room then there should be 147 men in the room left.

--> ##\frac{147}{297} \times 100=49.494949...##

--> That means the percentage of men in the room is 49.494949...%

Then the percentage of women is calculated like this:##\frac{3}{297} \times 100=1.1010101...%##

So the total percentage is 50.5050505...%?

- #17

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No, it is clear. Galois reasoned that the static number of women, 3, will be 2% of the new total. Thus, the new total is 150. Therefore the total decreased by (300 - 150) = 150. Done.I don't think so. I didn't understand his workings.

If 150 people left the room then there should be 147 men in the room left.

--> ##\frac{147}{297} \times 100=49.494949...##

--> That means the percentage of men in the room is 49.494949...%

Then the percentage of women is calculated like this:##\frac{3}{297} \times 100=1.1010101...%##

So the total percentage is 50.5050505...%?

If 150 men leave the room, there are (297-150) = 147 men in the room. If 150 men leave the room then there are (300-150) = 150 people left in the room total. 147 is 98% of 150. What is your objection? The expressions you wrote aren't about anything in this problem.

Last edited:

- #18

adjacent

Gold Member

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Oh, I got confused.I understand now. Sorry for making you confused too, galois! .No, it is clear. Galois reasoned that the static number of women, 3, will be 2% of the new total. Thus, the new total is 150. Therefore the total decreased by (300 - 150) = 150. Done.

If 150 men leave the room, there are (297-150) = 147 men in the room. If 150 men leave the room then there are (300-150) = 150 people left in the room total. 147 is 98% of 150. What is your objection?

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