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-   -   What is rate (https://www.askmehelpdesk.com/showthread.php?t=420177)

  • Nov 28, 2009, 07:34 PM
    JenisBeast
    What is rate
    If Jamar can run 3/5 of a mile in 2 minutes 30 seconds, what is his rate in miles per minute?
  • Nov 28, 2009, 08:17 PM
    QLP

    First think about what you have to do to 2 minutes 30 seconds to make it into 1 minute. You will need to remember that 30 seconds is half a minute.

    If I had to turn 1 minute and 30 seconds into 1 minute I would have to divide it by 1 and a half. So to turn 2 minutes and 30 seconds into 1 minute I would have to...

    Then whatever you divides the minutes by you need to divide the miles by.

    Here the tricky bit is that you are dividing a fraction by another fraction.

    Here's an example of how to divide fractions:

    2/3 divided by 5/3 is the same as
    2/3 multiplied by 3/5 since to divide by a fraction you turn it upside down and multipy

    To do 2/3 x 5/3 you multiply the top 2 numbers and put that on top then multiply the bottom 2 numbers and put that on the bottom

    So 2/3 x 5/3 = 10/9

    I hope that has given you enough explanation to work it out.
    take it one step at a time don't try to understand everything I put at once.
  • Nov 28, 2009, 08:29 PM
    KISS

    That's confusing:

    The initial problem is you don't have the right units for 2 min, 30 seconds. The answer needs to be in per minutes and your dealing with fractions.

    2 min 30 sec is 2.5 min, so we COULD get the answer by dividing (3/5) mile by 2.5 min and we would have units of miles/minute.

    Problem, it's not an exact answer. 2 and a half minutes is 4/2+1/2 minutes or 5/2 minutes.

    So the answer would be 3/5 mile divided by 5/2 minute. Which is

    3/5*2/5 or 6/25 miles per min. (invert the 5/2 and multiply)
  • Nov 28, 2009, 08:44 PM
    QLP

    I can see there was a gap in my explanation.
    When I said I would need to divide 1 and a half minutes by one and a half to get 1 minute I should have also pointed out that 1 and a half is the same as 3/2 because that's the same as 2/2 (which is 1)+1/2.

    So I would be dividing by 3/2 but you need to decide what to divide by for 2 and a half minutes.

    I didn't want to give you too much of the answer because you need to be able to understand this stuff and work it out for yourself.
  • Nov 29, 2009, 06:04 AM
    mathwiz3502
    .6 1
    over 2.5 to over x
    now, does the reciprical of a number multiplied with the number make one
    so 3/5 goes times 5/3 akes 1 so 5/3 must be multiplied with 5/2 to get x
    5 5 25
    2 x 3 = 6
    or 4 1/6
    4 10 minutes
    4.17 miles/miute
    give me feedback

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