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Homework Help: Walked or played

  1. Aug 17, 2009 #1
    1. The problem statement, all variables and given/known data
    I visited my friends home during my holidays.Our schedule went like this. We went for a walk in morning and played badminton in the evening. However due to the tiring nature of these, we did only 1 of them each day, i.e either walked or played Badminton. On some days we did neither!On 11 mornings we did nothing, 10 evenings we did nothing, we walked or played Badminton on a total of 11days. How long did i stay@ my friends place?

    2. Relevant equations
    How long did i stay @ my friends place?

    3. The attempt at a solution
    1 activity each day.
    total activities=11 events=11 days (morning+evening)
    11 mornings+10 eveings did nothing= 10 days + 1 morning.
    so, i guess.. 11+11=22 days??

    pls confirm the same.
  2. jcsd
  3. Aug 17, 2009 #2
    You should try to create a system of linear equations. Define a variable for each "activity", and do the sum.

    If you do nothing in a morning, it doesn't say that you did nothing in the evening. Your answer is wrong.
  4. Aug 17, 2009 #3
    If you do nothing in a morning, it doesn't say that you did nothing in the evening.

  5. Aug 17, 2009 #4
    activity of 11 days = 11 Morn(M) and 11 evenings(E)
    i.e. walk 6 M AND badminton 5 Evenings. This leaves 5 M AND 6 E.


    walk 5M and Badminton 6 E. this leaves 6M and 5E- no activity.

    considering first posssibilty leads nowhere.

    But if we consider 2nd possibility;
    now, 11 M and 10 E did nothing, including the activity days.
    this leaves full day of no activity - 5 M and 5 E= 5 days

    the total days= 11+5days=16 days.

    pls confirm.
    Last edited: Aug 17, 2009
  6. Aug 17, 2009 #5
    The answer is correct but the solution is guesswork. The goal of this exercise is to be able to create a mathematical model for the problem.

    You have three kinds of day. 1- Walk, 2- Badminton, 3- Nothing. These are your three unknowns, there's also three equations in the question. It will be a lot easier that way than guessing and never be really sure of your answer. Try it!
  7. Aug 17, 2009 #6
    thanks for guidance
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