I'm looking at a multiple choice test here and heres one of the questions(adsbygoogle = window.adsbygoogle || []).push({});

Q.) Your hair grows 5mm per week. What is its speed in m/s?

I calculating everything to appropriate units and got

time = 604800 seconds

length = 0.005 metres

then to get the rate of metres per second I divided 0.005m / 604800s and got

8 x 10^{-9 }m/s

None of the multiple choices match that answer though. The closest answer is 5 x 10^{-9 }m/s

I assume I did something wrong here but I can't see what.

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# Calculating meters per second

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