Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Significant digits in calculation

  1. Jan 25, 2010 #1
    Hello everyone:
    I am trying to figure out the how many significant figures (sf), should I keep in the final
    answer for multiplication and division
    1. How many hours and minutes are 20 kiloseconds?



    2.



    3. for hours: 20*10e3 / 3600 = 5.5555 hrs
    20 has only 1 significant figure (trailing zero doesn't count), hence the answer should have 1 sf, that means I should round answer to the single digits. my final answer is 6 hr. My book give 5.6 hr as the answer.
    please let me know my approach is correct

    for minutes 20*10e3 / 60 = 333.333 minutes
    keep only 1 sf in the result,that leads my answer to 333 minutes
    my book give 330 and the final answer
     
  2. jcsd
  3. Jan 26, 2010 #2

    Ouabache

    User Avatar
    Science Advisor
    Homework Helper

    Your book appears to be choosing 2 significant digits. However you could just as well choose 3 sf and still be correct. I would state what I'm using for sf, in my solution. To 3 sf, hours would be 5.56hr. If you see the answer in your book as 5.6hr, you should realize, both answers are correct.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook