finding percents need help I don't get it??
- Thread starter gjones
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gjones said:
First, you need to recognise - what is being asked to find
find the length of the Rio Grand.
Then next thing to do is to name that - as a variable
Let
the length of the Rio Grand = L
Now look at the problem again and find statement/s that relate this unknown L) to known numbers.
Missouri River it is 2,540 miles long ,which is 134% of the length of the Rio Grand (L)
Write that mathematically:
Length of Missouri= 134% x (Length of Rio Grand).......................................(1)
Now put numbers and variables in the equation above and solve for the variable.
Continue from here and show us what you get....
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The longest river in the United States is the Missouri River. It is 2,540 miles long, which is 134% of the length of the Rio Grand. Find the length of the Rio Grand to the nearest foot. How do you do this? My mind is blank.
Hi gjones:
Let's review. The word "percent" means "per 100", so the % symbol is like an arithmetic symbol that stands for "divide by 100".
4% = 4/100 = 0.04
26% = 26/100 = 0.26
49.5% = 49.5/100 = 0.495
500% = 500/100 = 5.00
134% = 134/100 = 1.34
and so on ...
We always divide by 100 to get rid of the % before doing arithmetic with percents.
Most basic "percent" problems involve three components: a NUMBER, a PERCENT, and the resulting PERCENTAGE.
Here is the equation that shows the relationship between these three components; this is the equation we use when we set up a "basic" percent problem.
\(\displaystyle \mbox{NUMBER}\;\times\;\mbox{PERCENT}\;=\;\mbox{PERCENTAGE}\)
For example, if you need to find 25% of 400, then you've been given the NUMBER (400) and the PERCENT (25%), and you need to find the PERCENTAGE.
\(\displaystyle 400\;\times\;\frac{25}{100}\;=\;\mbox{PERCENTAGE}\)
\(\displaystyle 400\;\times\;0.25\;=\;100\)
So, 25% of 400 is 100.
With most of these basic percent problems, you are given two of the three components, and you need to find the missing component. Here are the three possibilities:
(1) You have the NUMBER and the PERCENT; you need to use these to calculate the PERCENTAGE.
(2) You have the NUMBER and the PERCENTAGE; you need to use these to calculate the PERCENT.
(3) You have the PERCENT and the PERCENTAGE; you need to use these to calculate the NUMBER.
The example above, "What is 25% of 400?", is an example of possibility (1).
An example of possibility (2) is, "288 is what percent of 500?". You're given the NUMBER (500) and the PERCENTAGE (288); what is the PERCENT?
An example of possibility (3) is, "52.14 is 33% of what number?". You're given the PERCENTAGE (52.14) and the PERCENT (33%); what is the NUMBER?
Use the basic equation above to help you relate the values that you're given. This helps you see how to calculate the answer.
288 is what percent of 500?
\(\displaystyle \mbox{NUMBER}\;\times\;\mbox{PERCENT}\;=\;\mbox{PERCENTAGE}\)
\(\displaystyle 500\;\times\;\mbox{PERCENT}\;=\;\mbox{288}\)
\(\displaystyle \mbox{PERCENT}\;=\;\frac{288}{500}\)
\(\displaystyle \mbox{PERCENT}\;=\;0.576\)
(If you want to write this percent with a percent sign, then multiply it by 100 first).
The answer is 57.6% because 288 is 57.6% of 500.
52.14 is 33% of what number?
\(\displaystyle \mbox{NUMBER}\;\times\;\mbox{PERCENT}\;=\;\mbox{PERCENTAGE}\)
\(\displaystyle \mbox{NUMBER}\;\times\;\frac{33}{100}\;=\;52.14\)
\(\displaystyle \mbox{NUMBER}\;\times\;0.33\;=\;52.14\)
\(\displaystyle \mbox{NUMBER}\;=\;\frac{52.14}{0.33}\)
\(\displaystyle \mbox{NUMBER}\;=\;158\)
The answer is 158 because 52.14 is 33% of 158.
The problem that you asked about falls into possibility (3) above.
You are told that 134% of the length of the Rio Grand is the same as the length of the Missouri River (2540 miles).
So, you should be asking yourself, "134% of what number is the same as 2,540?" or, asked another way, "2,540 is 134% of what number?"
You are given the PERCENTAGE (2540) and the PERCENT (134%). You need to find the NUMBER.
Try to use the basic equation as I did to write out the relation between these two given values and the number you want to find. When you've finished the arithmetic, don't forget to round off your answer to the nearest foot.
Let us know if you need more help with this problem. If you do, then please show us what steps you were able to try.
Cheers,
~ Mark
Hi gjones:
Let's review. The word "percent" means "per 100", so the % symbol is like an arithmetic symbol that stands for "divide by 100".
4% = 4/100 = 0.04
26% = 26/100 = 0.26
49.5% = 49.5/100 = 0.495
500% = 500/100 = 5.00
134% = 134/100 = 1.34
and so on ...
We always divide by 100 to get rid of the % before doing arithmetic with percents.
Most basic "percent" problems involve three components: a NUMBER, a PERCENT, and the resulting PERCENTAGE.
Here is the equation that shows the relationship between these three components; this is the equation we use when we set up a "basic" percent problem.
\(\displaystyle \mbox{NUMBER}\;\times\;\mbox{PERCENT}\;=\;\mbox{PERCENTAGE}\)
For example, if you need to find 25% of 400, then you've been given the NUMBER (400) and the PERCENT (25%), and you need to find the PERCENTAGE.
\(\displaystyle 400\;\times\;\frac{25}{100}\;=\;\mbox{PERCENTAGE}\)
\(\displaystyle 400\;\times\;0.25\;=\;100\)
So, 25% of 400 is 100.
With most of these basic percent problems, you are given two of the three components, and you need to find the missing component. Here are the three possibilities:
(1) You have the NUMBER and the PERCENT; you need to use these to calculate the PERCENTAGE.
(2) You have the NUMBER and the PERCENTAGE; you need to use these to calculate the PERCENT.
(3) You have the PERCENT and the PERCENTAGE; you need to use these to calculate the NUMBER.
The example above, "What is 25% of 400?", is an example of possibility (1).
An example of possibility (2) is, "288 is what percent of 500?". You're given the NUMBER (500) and the PERCENTAGE (288); what is the PERCENT?
An example of possibility (3) is, "52.14 is 33% of what number?". You're given the PERCENTAGE (52.14) and the PERCENT (33%); what is the NUMBER?
Use the basic equation above to help you relate the values that you're given. This helps you see how to calculate the answer.
288 is what percent of 500?
\(\displaystyle \mbox{NUMBER}\;\times\;\mbox{PERCENT}\;=\;\mbox{PERCENTAGE}\)
\(\displaystyle 500\;\times\;\mbox{PERCENT}\;=\;\mbox{288}\)
\(\displaystyle \mbox{PERCENT}\;=\;\frac{288}{500}\)
\(\displaystyle \mbox{PERCENT}\;=\;0.576\)
(If you want to write this percent with a percent sign, then multiply it by 100 first).
The answer is 57.6% because 288 is 57.6% of 500.
52.14 is 33% of what number?
\(\displaystyle \mbox{NUMBER}\;\times\;\mbox{PERCENT}\;=\;\mbox{PERCENTAGE}\)
\(\displaystyle \mbox{NUMBER}\;\times\;\frac{33}{100}\;=\;52.14\)
\(\displaystyle \mbox{NUMBER}\;\times\;0.33\;=\;52.14\)
\(\displaystyle \mbox{NUMBER}\;=\;\frac{52.14}{0.33}\)
\(\displaystyle \mbox{NUMBER}\;=\;158\)
The answer is 158 because 52.14 is 33% of 158.
The problem that you asked about falls into possibility (3) above.
You are told that 134% of the length of the Rio Grand is the same as the length of the Missouri River (2540 miles).
So, you should be asking yourself, "134% of what number is the same as 2,540?" or, asked another way, "2,540 is 134% of what number?"
You are given the PERCENTAGE (2540) and the PERCENT (134%). You need to find the NUMBER.
Try to use the basic equation as I did to write out the relation between these two given values and the number you want to find. When you've finished the arithmetic, don't forget to round off your answer to the nearest foot.
Let us know if you need more help with this problem. If you do, then please show us what steps you were able to try.
Cheers,
~ Mark