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-   -   Distance and Work (https://www.askmehelpdesk.com/showthread.php?t=110893)

  • Jul 17, 2007, 03:30 PM
    nike23
    Distance and Work
    1. A squirrel made a trip of 275 miles in 8 hrs. before noon he averaged 40 mph and after noon he averaged 25 mph. at what time did he begin his trip and when did he end it?

    okay, I worked my way to this:n 40(x)+25(8-x)=275
    I tried combining them but the answer didn't work: 65(8-x)=275
    the number has tons of numbers after the decimals for x

    OTHER-----------------------------------------------------------------------------------------

    1. vicki can paint a room in 3 hrs. janey can paint the same room in 4hrs. How long does it take for both girls to pain 2/3 the room if they are working together?

    3/1+4/1=1.5/2+2/2=3.5/2=1.75=1 hr 45 min. 2/3 or 1 hr 45 min is ?

    2. Anthony can paint a house in 5 hrs. Ryan can paint the same one in 6 hrs. anthony worked alone for 2 hrs and quit. How long does it take ryan to complete the rest of the house alone?

    5/1+6/1=2.5/2+3/2 anthony worked alone for 2 hrs. do I use the 5/1 or the 2.5/2? And how do I subtract that 2 hrs? From ryan or from anothy?

    3. nicole can pick all the apples on a farm in 14 days. Rebecca can do it in 7 days and aaron can do it in 10 days. If they all worked together, how many days would it take to pick the apples on the farm?

    14/1+7/1+10/1 none of them go into 3 all of the answers will be either 3.3 repeating or any number that is irrational
  • Jul 17, 2007, 04:16 PM
    CaptainRich
    Here. Try this... :
    https://www.askmehelpdesk.com/math-s...board-b-u.html

    Good luck.
  • Jul 17, 2007, 10:52 PM
    Capuchin
    We will put as much effort into answering you as you put into doing your own work.

    i.e.. None.

    You know how this works!
  • Jul 18, 2007, 06:28 AM
    nike23
    okay, I showed some work on it and told u what I don't understand about it. I also took out the ones that I have already figured out. Now u do the explaining ^_^
  • Jul 18, 2007, 08:09 AM
    Capuchin
    Quote:

    Originally Posted by nike23
    okay, i worked my way to this:n 40(x)+25(8-x)=275
    i tried combining them but the answer didnt work: 65(8-x)=275

    You made a mistake here. You need to expand the brackets before you simplify. If there are lots of digits after the decimal place, that doesn't matter, you just round off after a few decimal places (I assume that you are not old enough to know about how to estimate accuracy).

    Quote:

    Originally Posted by nike23
    1. vicki can paint a room in 3 hrs. janey can paint the same room in 4hrs. how long does it take for both girls to pain 2/3 the room if they are working together?

    3/1+4/1=1.5/2+2/2=3.5/2=1.75=1 hr 45 min. 2/3 or 1 hr 45 min is ?

    None of your manipulations here make sense? "3/1+4/1=1.5/2+2/2" is clearly wrong. You can use speed = distance/time, where time is the number of hours they take, and distance is that amount of rooms they paint. You can then add their speeds and use the formula to work out the time for 2/3 of a room.
    Try again, the answer should be just over an hour.

    Your other 2 questions are similarly incorrect. Use the speed = distance/time idea and see where you get with it.
    Let me know if you need further help.
  • Jul 18, 2007, 08:46 AM
    galactus
    The squirrel problem could be set up as such:

    40(8-t) is the distance traveled before noon and 25t is the distance traveled after noon.



    Solve for t.
  • Jul 18, 2007, 08:48 AM
    Capuchin
    He's already set it up like that gal! Check out the original question! (except he set it up the other way around, which is fine as long as his answer reflects that.)
  • Jul 18, 2007, 09:18 AM
    nike23
    Quote:

    Originally Posted by Capuchin
    None of your manipulations here make sense? "3/1+4/1=1.5/2+2/2" is clearly wrong. You can use speed = distance/time, where time is the number of hours they take, and distance is that amount of rooms they paint. You can then add their speeds and use the formula to work out the time for 2/3 of a room.
    Try again, the answer should be just over an hour.

    Your other 2 questions are similarly incorrect. Use the speed = distance/time idea and see where you get with it.
    Let me know if you need further help.

    OK, this would mean further help, for the time does it mean I have to add both of their hours? Like 3+4=7 hrs together?
  • Jul 18, 2007, 09:21 AM
    Capuchin
    No you treat them separately to find their separate speeds, then you can add their speed and find the new time.
  • Jul 18, 2007, 04:42 PM
    galactus
    Quote:

    3. nicole can pick all the apples on a farm in 14 days. Rebecca can do it in 7 days and aaron can do it in 10 days. If they all worked together, how many days would it take to pick the apples on the farm?

    14/1+7/1+10/1 none of them go into 3 all of the answers will be either 3.3 repeating or any number that is irrational
    Try setting it up like this and solving for t:



    The answer is not irrational.
  • Jul 19, 2007, 07:22 PM
    galactus
    Quote:

    2. Anthony can paint a house in 5 hrs. Ryan can paint the same one in 6 hrs. anthony worked alone for 2 hrs and quit. How long does it take ryan to complete the rest of the house alone?
    Anthony can paint the house in 5 hours. He worked alone for 2 hrs, then quit. That means he completed 2/5 of the house, so there's 3/5 remaining to paint.

    Since Ryan can paint a whole house in 6 hours. He will have to paint 3/5 of the house.

    6(3/5)=18/5=3.6


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