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Express 68 degree F in degree C.Multiple Choice: A) 7.0  degree C B) 20 degree C C) 36...

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jayjay00 | Student, Undergraduate | eNotes Newbie

Posted December 12, 2009 at 1:29 AM via web

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Express 68 degree F in degree C.

Multiple Choice:

A) 7.0  degree C

B) 20 degree C

C) 36 degree C

D) 181 degree C

4 Answers | Add Yours

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pohnpei397 | College Teacher | (Level 3) Distinguished Educator

Posted December 12, 2009 at 1:45 AM (Answer #1)

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The correct answer for this is B -- the temperature is expressed as 20 degrees Celsius.

The formula for this conversion is

Tc = (Tf-32)/(9/5) where Tc is the temperature in Celsius and Tf is the temperature in Fahrenheit.  This can also be expressed as (Tf-32)/1.8

When we do the math based on this conversion formula, we subtract 32 from 68.  This gives us 36.  We then divide 36 by 1.8 and this gives us 20.

Therefore, the temperature that is expressed as 68 degrees Fahrenheit is also expressed as 20 degrees Celsius.

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lynn30k | High School Teacher | (Level 3) Associate Educator

Posted December 12, 2009 at 7:43 AM (Answer #3)

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The correct formula is C = (5/9)(F-32). If we substitute 68 for F, since that is the temp you are given, we have

C = (5/9) (68-32)

C = (5/9) 36

C= 180/9

C = 20 degrees

 

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krishna-agrawala | College Teacher | Valedictorian

Posted December 13, 2009 at 12:38 AM (Answer #4)

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In centigrade system of measurement (C) the temperature at which water solidifies is taken as 0 C, and the temperature at which water boils is taken as 100 C. Against this In Fahrenheit system of measurement (F) the temperature at which water solidifies is taken as 32 F, and the temperature at which water boils is taken as 312 F. This means that the difference in temperature of solidifying and boiling of water is divided in 100 parts in C system, it is divided 180 parts in F system. This means magnitude of each degree F is equal to 5/9 times degrees C.

Thus we can convert any temperature in Fahrenheit in to centigrade using the following formula:

C = (F - 32)*5/9

Therefore when F = 68, C is given by:

C = (68 - 32)*5/9 = 36*(5/9) = 20

Answer:

Choice C (20 degrees C) is correct.

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kristy5137 | High School Teacher | eNotes Newbie

Posted December 13, 2009 at 4:26 PM (Answer #5)

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jayjay,

when converting from Celsiusto Fahrenheit, the best way to do it is to realize that they have similar log scales and can be determined by knowing only one step, actually.

To go from F to C                 to go from C to F

1) add 40                            1) add 40

2) multiply by 5/9                  2) multiply by 9/5

3) subtract 40                       3) subtract 40

You see from this that there is no need to remember any equation other than multiplying by either 5/9 or 9/5 since step 1 and step 3 are identical. How do you know which one to use?  Just notice if you go from large scale to small scale use 5/9 and if you go from a large scale to a small scale then use 9/5.

Therefore the answer to your question is:

1) 68 +40= 108

2) 108 * (5/9)= 60

3) 60-40=20 C

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