Uniform Motion

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TamaraHill

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Steve and Aaron drove a boat acrosss the lake. Their speed on the return trip was 5mph moe than the first trip across the lake. It took them 3hours to cross the lake and 2hours on the return trip. what were both speed?

I have going-- rate=x, Time 3hrs, Distance 3x
I have Returning--- Rate =5+x, Time=2hrs, Distance=2(x+5)
than i am stuck
 
TamaraHill said:
I have going-- rate=x, Time 3hrs, Distance 3x
I have Returning--- Rate =5+x, Time=2hrs, Distance=2(x+5)
than i am stuck
Click to expand...
Since distance is SAME, then 3x = 2(x+5) ; kapish?
 
Denis said:
TamaraHill said:
I have going-- rate=x, Time 3hrs, Distance 3x
I have Returning--- Rate =5+x, Time=2hrs, Distance=2(x+5)
than i am stuck
Click to expand...
Click to expand...
Since distance is SAME, then 3x = 2(x+5) ; kapish?[/3x=2x+10] how do i solve
 
porportion

To estimate the number of elk in a wildlife refuge, park rangers catch, tag , and then release 40 elf. one month later, they observe a sample of 80elk, 4 which are tagged. Assuming the ratio of tagged elk in the sample holds for all elk in the refuge, approximately how many elk are in the refuge?
 
TamaraHill said:
approximately how many elk are in the refuge?
Click to expand...

In the future, please start a new thread for each new exercise.

First, assign a variable to represent the elk population.

x = the elk population

Next, assume that the two ratios are equal, and write a proportion.

One of these ratios is: [number of tagged elk in the sample]/[number of elk in the sample]

The other ratio is: [number of elk they tagged]/[the elk population]

Finish, by solving the proportion for x.

I welcome your specific questions about this. 8-)
 
Re:

mmm4444bot said:
TamaraHill said:
approximately how many elk are in the refuge?
Click to expand...

In the future, please start a new thread for each new exercise.

First, assign a variable to represent the elk population.

x = the elk population

Next, assume that the two ratios are equal, and write a proportion.

One of these ratios is: [80]/[4
]The other ratio is: [40/xFinish, by solving the proportion for x.

I welcome your specific questions about this. 8-)
Click to expand...
would answer be 2
 
TamaraHill said:
[80]/[4]

40/x

would answer be 2 No.
Click to expand...

There must be more than two elk in the refuge. After all, they tagged 40 elk and later observed 80 elk. I'm surprised that you might think there are only two elk in the refuge.

It looks like you flipped the ratio: [number of tagged elk in sample]/[number of elk in sample] and wrote 80/4 instead of 4/80.

 


Note: If you would like to use the ratio [elk in sample]/[tagged elk in sample], instead, then the other ratio would need to be [elk population]/[number of elk they tagged].

In other words, there are two proportions possible in this exercise, and either one of them works.

4/80 = 40/x

OR

80/4 = x/40

 
Re:

mmm4444bot said:


Note: If you would like to use the ratio [elk in sample]/[tagged elk in sample], then the other ratio would need to be [elk population]/[number of elk they tagged].

In other words, there are two proportions possible in this exercise, and either one works.

4/80 = 40/x

OR

80/4 = x/40
Click to expand...
x=800
 
TamaraHill said:
x = 800 ? This is correct.
Click to expand...

Most instructors like to see the final answer to word problems written as a complete sentence because doing so shows that you understand the meaning of your results.

"There are approximately 800 elk in the refuge."

:D

 
I agree. Even x = 800 elk will show understanding beyond mechanics.
 
Re: porportion

TamaraHill said:
To estimate the number of elk in a wildlife refuge, park rangers catch, tag , and then release 40 elf. one month later, they observe a sample of 80elk, 4 which are tagged. Assuming the ratio of tagged elk in the sample holds for all elk in the refuge, approximately how many elk are in the refuge?
Click to expand...

How did they catch elk - after releasing elves???

Tamara - please start a new thread with a new problem.
 
percent discount

Scott is going to Florida in March. On line, he finds a room in a hotel that is normally 140 per night for $58.20 per night. What is the rate of discount on the room?


58.20x=140.00=2.40%
 
Re: porportion

Subhotosh Khan said:
TamaraHill said:
To estimate the number of elk in a wildlife refuge, park rangers catch, tag , and then release 40 elf. one month later, they observe a sample of 80elk, 4 which are tagged. Assuming the ratio of tagged elk in the sample holds for all elk in the refuge, approximately how many elk are in the refuge?
Click to expand...

How did they catch elk - after releasing elves???

Tamara - please start a new thread with a new problem.
Click to expand...
How do i start a new thread? Sorry didnt know how
 
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