Results 1 to 6 of 6

Math Help - Finding the total

  1. #1
    Junior Member
    Joined
    Mar 2010
    Posts
    64

    Finding the total

    Monday: 25 students absent
    Tuesday: 20 students absent
    Wednesday: 10 students absent
    Thursday: 15 students absent
    Friday: 20 students absent

    Of the given above absences, 8 students were absent exactly 2 days each, 1 was absent 3 days, and no students were absent more than 3 days. If 5 percent of the students in the school were absent at least 1 day last week, how many students are enrolled in this school?

    How can it be 1600??
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor MarkFL's Avatar
    Joined
    Dec 2011
    From
    St. Augustine, FL.
    Posts
    1,988
    Thanks
    734

    Re: Finding the total

    There are a total of 90 reported absences for the week. To find how many students this involves, we subtract the 8 that are counted twice, and 2 for the one student that was counted 3 times. This means 90 - (8 + 2) = 80 students were involved in the absences. So, we are left with 80 is 5% of what number. Since 5% is 1/20, we find the number of students in the school is 20·80 = 1600.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Mar 2010
    Posts
    64

    Re: Finding the total

    I'm still rather lost, the last couple of sentences do not make sense to me Maybe if we could solve it more algebraically?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor MarkFL's Avatar
    Joined
    Dec 2011
    From
    St. Augustine, FL.
    Posts
    1,988
    Thanks
    734

    Re: Finding the total

    80 = x/20

    1600 = x
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Mar 2010
    Posts
    64

    Re: Finding the total

    Why do we subtract 2? What about the "2 days each" "3 days" "at least 1 day". These seem to be throwing me off as to why the solution is the way it is.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor MarkFL's Avatar
    Joined
    Dec 2011
    From
    St. Augustine, FL.
    Posts
    1,988
    Thanks
    734

    Re: Finding the total

    We subtract 1 for each person absent twice because each person has two absences associated with them in the total of 90, but only represent one person each. For the person absent 3 times, there are 3 absences associated with them, so we need to subtract 2 so that we only count them once.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Finding total outward flux?
    Posted in the Calculus Forum
    Replies: 3
    Last Post: December 13th 2009, 11:03 AM
  2. Finding Total Cost Mean Std Deviation
    Posted in the Statistics Forum
    Replies: 2
    Last Post: August 3rd 2009, 04:51 PM
  3. Replies: 3
    Last Post: May 1st 2009, 09:04 AM
  4. Replies: 1
    Last Post: February 20th 2009, 10:35 AM
  5. Finding total surface area of a sphere +more
    Posted in the Geometry Forum
    Replies: 1
    Last Post: October 31st 2008, 10:06 PM

Search Tags


/mathhelpforum @mathhelpforum