1. Not finding help here? Sign up for a free 30min 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!

Math percent increase problem

  1. Oct 21, 2005 #1
    Can someone explain to me the following:
    If a number increases from 108,7 to 113,7 how much in percent has it increased?

    First I tried to do 108,7 / 113,7 = 0,956.
    1 - 0,956 = 0,0439. In other words, an increase of 4,39%. This turns out to be wrong. 113,7 / 108,7 = 1,0459 -> an increase of 4,59% is correct, but I fail to see the logic in that the last approach is correct. What am I actually calculating in my first try?
     
  2. jcsd
  3. Oct 21, 2005 #2
    In your first try you're finding that 108.7 is 0.956*100 = 95.6% out of 113.7.

    Look at the increase from 108.7 to 113.7, it's a increase by 5 units. (113.7-108.7). Now, if we want to find how many % 5 is out of 108.7, we do (5/108.7)*100 = 4.59%. So, in general:
    If a number increases from a to b, how many percent did it increase?
    Answer:
    [(b-a)/a]*100%
     
  4. Oct 21, 2005 #3
    Aha, thanks alot Karlsen!
     
  5. Oct 21, 2005 #4
    Always nice to help a fellow citizen.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Math percent increase problem
  1. Maths problem (Replies: 2)

  2. Math problems (Replies: 5)

  3. Math problem (Replies: 6)

  4. Math Problem (Replies: 5)

Loading...