Posted by **Kacey** on Friday, May 1, 2009 at 2:05am.

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 -
**RickP**, Friday, May 1, 2009 at 3:10am
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 -
**Damon**, Friday, May 1, 2009 at 6:36am
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

## Answer this Question

## Related Questions

- Intermediate Algebra - Joe can paint a room in 6 hours while Sue can paint the ...
- math - If painter A can paint a room in three hours by themselves, and painter B...
- math - Arthur can paint a room in 6 hours. Boris can paint the same room in 8 ...
- math - Shelby can paint a room in 4 hours. Zoe can paint the same room in 7 ...
- Algebra - If Dale can paint a room in 5 hours alone and Chip can paint the same ...
- Math - Al can paint a room in a hours working alone. Bill can paint a room in b ...
- algebra 2/trig - Tina can paint a room in 8 hours, but when she and her friend ...
- algebra2/trig - tina can paint a room in 8 hours, but when she and her friend ...
- Word problem - Edward can paint a bedroom in 3hr. Jeb can paint the same room in...
- math - nadia can paint a room in 5 hours Nat can paint the same room in 7 hours ...