Welcome to Westonci.ca, where curiosity meets expertise. Ask any question and receive fast, accurate answers from our knowledgeable community. Experience the convenience of finding accurate answers to your questions from knowledgeable professionals on our platform. Get quick and reliable solutions to your questions from a community of experienced experts on our platform.

Lyle can paint a room in 3 hours. Selena can paint a room with the same dimensions in 2 hours. If they work together, how many hours does it take them to paint the room? Round your answer to the nearest tenth.

Sagot :

ANSWER
1.2 hours

EXPLANATION 
Let x represent the number of hours it takes to complete the paint job.
The fraction of a job done per hour with both of them working is 1/x.

Lyle does 1/3 of the painting in one hour
(For example, if it took 3 hours to paint the room, then in one hour, only 1/3 of the room will be painted. In two hours, 1/3 + 1/3  = 2/3 of the room will be painted. In three hours, 1/3+1/3+1/3=3/3=1 of the room will be painted---completed)

Selena does 1/2 of the painting in one hour.

Therefore, for one hour, the fraction of the Job that Lyle does added with the fraction of the Job that Selena does is equal to 1/x, which is the fraction of the job done with both of them working

   1/3 + 1/2 = 1/x

Multiply both sides of the equation by x

   x/3 + x/2 = 1

Factor out x from the left side

   x(1/3 + 1/2) = 1

Combine fractions. Get a common denominator for 1/3 and 1/2.
LCD of 1/3 and 1/2 is 6. 1/3 is equivalent to 2/6 and 1/2 is equivalent to 3/6.

   x(2/6 + 3/6) = 1
   x (5/6) = 1
   x = 1 * 6/5
   x = 6/5
   x = 1.2 hours

ALTERNATIVE EXPLANTION:
   job = rate · time ⇔ rate = job/time ⇔ time = job/rate

Lyle can do 1 paintjob of the room in 3 hours. Therefore, Lyle's rate is 1/3 paintjob per hour.

Selena can do 1 paintjob of the room in 2 hours. Therefore, Selena's rate is 1/2 paintjob per hour.

Their rate when working together is combined:

   rate = 1/3 + 1/2 = 2/6 + 3/6 = 5/6

Since time = job/rate and we are interested in 1 paintjob, then job = 1 and

   time = 1 / (5/6) = 6/5 = 1.2 hours