Results 1 to 6 of 6
Like Tree1Thanks
  • 1 Post By Reckoner

Math Help - If 200 of something costs 53.80. then how much does 20 of the same thing cost?

  1. #1
    Junior Member
    Joined
    Nov 2008
    Posts
    39

    If 200 of something costs 53.80. then how much does 20 of the same thing cost?

    OK this is dumb beyond belief, but I have been offered a cheap deal on something that seems too good to be true. Basically for each pack of 200 I pay 53.80, but I want to know how much 20 costs. To do this I assumed all I had to do was divide 200 by 53.80 to get the price for one of these items and then multiply this by 20 to get the cost of 20. But this works out at a stupidly cheap price of about 73 pence for 20. I know this is dumb and it can't possibly be right, as I have never seen these items sold so cheaply. What am I doing wrong?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor Reckoner's Avatar
    Joined
    May 2008
    From
    Baltimore, MD (USA)
    Posts
    1,024
    Thanks
    75
    Awards
    1

    Re: If 200 of something costs 53.80. then how much does 20 of the same thing cost?

    Quote Originally Posted by jebus197 View Post
    divide 200 by 53.80 to get the price for one of these items
    Wrong way. If the unit cost is u, we have 200u=53.80\Rightarrow u=\frac{53.80}{200}=0.269.

    So 20u = 20\cdot0.269=\pounds5.38.

    Another way of looking at it is to note that 20 is 10% of 200. So 20 units should cost 10% of 53.80, which would be 5.38.
    Thanks from jebus197
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Nov 2008
    Posts
    39

    Re: If 200 of something costs 53.80. then how much does 20 of the same thing cost?

    Thanks, seems obvious now, lol.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    May 2012
    From
    US
    Posts
    1

    Re: If 200 of something costs 53.80. then how much does 20 of the same thing cost?

    Great! it's simple, clear. Thanks for sharing
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Apr 2012
    From
    Irving TX
    Posts
    42
    Thanks
    1

    Re: If 200 of something costs 53.80. then how much does 20 of the same thing cost?

    first we will take out the cost of one piece such as 53.80/200 = 0.269
    so then 20 piece cost will be 0.269 * 20 = 5.38
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor

    Joined
    Apr 2005
    Posts
    16,421
    Thanks
    1856

    Re: If 200 of something costs 53.80. then how much does 20 of the same thing cost?

    Quote Originally Posted by kalwin View Post
    first we will take out the cost of one piece such as 53.80/200 = 0.269
    so then 20 piece cost will be 0.269 * 20 = 5.38
    If you want to do it the hard way! Much simpler is to note that 20 is one-tenth of 200 so the cost of 20 is one-tenth the cost of 200. One-tenth of 53.80 is 5.38.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Microeconomics, fixed costs variable cost, how?
    Posted in the Business Math Forum
    Replies: 5
    Last Post: March 19th 2012, 12:47 PM
  2. [SOLVED] monthly costs vs Direct costs
    Posted in the Algebra Forum
    Replies: 1
    Last Post: July 1st 2011, 02:48 PM
  3. Replies: 1
    Last Post: December 7th 2009, 12:00 AM
  4. Process cost systems,total cost under the FIFO Method.
    Posted in the Business Math Forum
    Replies: 0
    Last Post: December 5th 2009, 12:13 AM
  5. Replies: 0
    Last Post: October 26th 2008, 05:29 PM

Search Tags


/mathhelpforum @mathhelpforum