Paula can paint a room in six hours. Paula starts painting the room at

9:00 AM. At 11:00 AM, Carlos accompanies Paula, and both of them,

working together, finish painting the room at 2:30 PM. Assuming both

painters always paint at a constant rate, how many hours can Carlos

paint the same room working by himself?

Guest Oct 31, 2020

#1**+1 **

Note that without Carlos 'helping' Paula would finish the room painting at 3 PM by herself....so Carlos is not a lot of help

after painting ofr 2 hours there is 4 hours left for Paula to finish the job

but it takes 3.5 hours with both of them

1/4 + 1/ C = 1/ 3.5

solve for C = 28 but this is for 2/3 of the job

Carlos alone would be 28 * 3/2 = 42 hours to paint the room....he must have a very small brush?

ElectricPavlov Oct 31, 2020

#2**0 **

Here is another way:

Since Carlos, working for 3.5 hours, saved her only 1/2 an hour, that means she does as much work in 1/2 an hour as Carlos does in 3.5 hours. Or Carlos rate is: 3.5 / 0.5 =7 times slower than that of Paula. And since she can paint the whole room in 6 hours, it would, therefore, take Carlos: 6 x 7 = 42 hours to finish the same room!!!!.

Guest Oct 31, 2020