math

posted by .

A can paint a room in 3 hours, and B can paint a room in 4 hours. How long will it take if they paint it together?

  • math -

    Use the equation

    Tt = 1/Tf + 1/Ts

    where Tt is the total time, Tf is the first person's time, and Ts is the second person's time. Now just plug and chug.

  • math -

    ah:
    { 1/Tt } = 1/Tf + 1/Ts

    because
    A --> 1/3 rooms per hr
    B --> 1/4 rooms/hr
    (A+B) --> 1/3 + 1/4 rooms/hr = 7/12 rooms per hr
    which is 12/7 hours/room

  • math -

    7/12

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Math

    Al can paint a room in a hours working alone. Bill can paint a room in b hours working alone. Working alone, Bill takes tow more hours to paint a room than Al. Working together, they can paint a room in 8 hours. Write down a system …
  2. Intermediate Algebra

    Joe can paint a room in 6 hours while Sue can paint the same room in 5 hours. Working together, how long would it take them to paint the room?
  3. math

    Shelby can paint a room in 4 hours. Zoe can paint the same room in 7 hours. How long will it take them to paint the room if they work together?
  4. math

    If painter A can paint a room in three hours by themselves, and painter B can paint the same room in four hours, and painter C can paint the same room in six hours, how long will it take for all three to paint the room together if …
  5. Algebra

    If Dale can paint a room in 5 hours alone and Chip can paint the same room in 7 hours alone. How long would it take them together to pain the room?
  6. algebra2/trig

    tina can paint a room in 8 hours, but when she and her friend emily work together, they can complete the job in 3 hours. how long would it take emily to paint the room alone?
  7. math

    Arthur can paint a room in 6 hours. Boris can paint the same room in 8 hours. If boris and arthur work together, how long will it take for them to paint the room
  8. algebra 2/trig

    Tina can paint a room in 8 hours, but when she and her friend Emily work together, they can complete the job in 3 hours. How long would it take Emily to paint the room alone?
  9. Math

    It take peter 5 hours to pain a Room. It takes Juan 3.75 hours to paint a Room. How much time would it take for them to paint the Room together?
  10. Algebra

    Sally can paint a room in 4 hours while it takes Steve 7 hours to paint the same room. How long would it take them to paint the room if they worked​ together?

More Similar Questions