1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Maths competition

  1. Jul 28, 2008 #1
    these are numbers i could not solve. please help me.

    1. The problem statement, all variables and given/known data

    1) If the repeating decimal 0.8451[tex]\bar{51}[/tex] is represented by the fraction a/b, where a and b are positive integers with no common factors greater than 1, find the sum a + b.

    2) if log(log(log(log x))) = 0 and log represents the base ten logarith, what is the value of x.

    3. The attempt at a solution

    1) i don't understand how to proceed. some hints would be appreciated.

    2)i kno that if, logba = x

    then, a = bx

    i got 10100 as answer but the paper says the answer is 1010,000,000,000 is the answer.

  2. jcsd
  3. Jul 28, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    For b why don't you show us how you can your answer, writing out every step in full.

    For a, it is the same as finding a number 0.51515151... (and then adding 84 and dividing by 100). Do you know how you would find such a number?
  4. Jul 28, 2008 #3
    2) log(log(log(log x))) = 0

    log(log(log x)) = 100 = 1

    log(log x) = 101 = 10

    log x = 1010

    x = 101010

    oooh ok.... now i see my mistake!!! i tried doing the calculation in my head.... so foolish of my part

    errm, for #1
    d'you mean that i should break the 0.8451515151 into 0.84 + 0.005151515151 ?!

  5. Jul 28, 2008 #4


    User Avatar
    Science Advisor
    Homework Helper

    Yes that's how I would approach the problem. Now can you find a fraction to represent 0.005151515.... ?
    If you don't know how, you should read the section entitled "Fraction from a repeating decimal" here
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Maths competition
  1. Math Competition (Replies: 10)