# Calculus 1: pulse of light traveling from the sun to the earth

#### sigma

Question: "Approximately how many minutes will it take a pulse of light to travel from the sun to the earth? (Do not perform any intermediate calculations, and do not round your answer.)"

I have no clue how to answer this question. I know how to solve the problem. time is distance divided by rate, I can simply search up the distance between the sun and earth in terms of kilometers, then divide it by the speed of light in terms of kilometers. But my answer was not accepted. I'm asked to use the unit conversions in my text, but I'm not sure how to make use of it. Here is the table of conversions I'm supposed to use

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#### weirddave

I'm intrigued as to what answer is accepted and how they got it, because there isn't enough information provided.

#### skeeter

Math Team
Question: "Approximately how many minutes will it take a pulse of light to travel from the sun to the earth? (Do not perform any intermediate calculations, and do not round your answer.)"
used this reference for the mean distance of an astronomical unit ...
$$\displaystyle (149,597,871 \text{ km}) \cdot \left(\dfrac{1 \text{ sec}}{299,752.5 \text{ km}} \right) \cdot \left(\dfrac{1 \text{ min}}{60 \text{ sec}}\right) = 8.317855064 \text{ min}$$​

topsquark

#### weirddave

Cheat, AU to km isn't listed in the conversion table!

topsquark

Math Team
Manure ...

weirddave

#### topsquark

Math Team
Cheat, AU to km isn't listed in the conversion table!
Doesn't everyone know that off the top of their head?

-Dan

#### weirddave

Clearly not, Skeeter provided his reference