Rounding a number

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Heartmind

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Hello! After resolving a Geometry problem I'm trying to round the answer 2160.509554140127 miles to the nearest mile. My answer is approximately 2160 miles, but the answers book says the answer is approximately 2159 miles. Can you please round the number for me? Thank you very much.
 
Heartmind said:
Hello! After resolving a Geometry problem I'm trying to round the answer 2160.509554140127 miles to the nearest mile. My answer is approximately 2160 miles, but the answers book says the answer is approximately 2159 miles. Can you please round the number for me? Thank you very much.
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The answer in the book is wrong.

Your answer is correct.

According to some method the approximate number could be 2161 (but not 2159).
 
Subhotosh Khan said:
The answer in the book is wrong.

Your answer is correct.
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Well... that actually may or may not be true. Given that we don't know the problem it came from, we have no way to verify that your (unrounded) answer is correct. If you are correct up to that point, then I concur with Subhotosh Khan that the book is wrong. However, you may have made a small mistake somewhere in your working, and thus your answer might be off be just enough to make your rounded answer wrong. We can't say conclusively without knowing what the initial problem was.
 
Heartmind said:
Hello! After resolving a Geometry problem I'm trying to round the answer 2160.509554140127 miles to the nearest mile. My answer is approximately 2160 miles, but the answers book says the answer is approximately 2159 miles. Can you please round the number for me? Thank you very much.
Click to expand...

Neither you nor the book is correct. Rounded to the nearest mile, the answer would be 2161 miles.
 
Subhotosh Khan said:
You can read a little about this here:

Rounding Up or Down on a 5
http://mathforum.org/dr.math/problems/slaber.6.13.99.html

and in this site linked in our Ask Dr. Math Rounding FAQ
(http://mathforum.org/dr.math/faq/faq.rounding.html ):

Rules for Rounding Numbers
http://www.uop.edu/cop/psychology/Statistics/Rounding.html
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Even if the issue was whether or not you round up on a 5 (which by the way, you do), it should be clear that this amount is MORE than 0.5 due to the extra digits. It is clearly closer to 2161 than 2160...
 
Prove It said:
Neither you nor the book is correct. Rounded to the nearest mile, the answer would be 2161 miles.
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Prove It, you cannot state as a surety that the book's answer is not correct.

After a repeated attempt at solving, the student may have the wrong value.

ksdhart's post is logical and his/her points are pertinent as to why.

The student's value is alleged.
 
Last edited:
Denis said:
For 1st time, I agree with LookOnceMore !
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Denis, I believe you when you state it was the first time that you agreed with lookagain.


I also believe everything that Hillary Clinton and Brian Williams (former NBC Nightly

News lead anchor who was fired for lying in multiple cases) have ever said.
 
Rounding

To the nearest mile means the units or ones place.
The answer is clearly 2161 miles.
 
mathdad said:
To the nearest mile means the units or ones place.
The answer is clearly 2161 miles.
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...assuming the steps leading to the student's original value were correct. If not, then... maybe not. ;)
 
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