Final answer:
To find out how long it will take Resty to paint the room when he works alone, we can use the concept of work rate. Assuming Resty's work rate is R jobs/hour and Alvin's work rate is A jobs/hour, we can set up equations based on the given information and solve them to find the value of R.
Step-by-step explanation:
To solve this problem, we can use the concept of work rate. Let's assume that Resty's work rate is R jobs/hour, and Alvin's work rate is A jobs/hour. From the given information, we know that Alvin's work rate is 3 hours less than Resty's work rate, so we can write A = R - 3.
When Alvin and Resty work together, their combined work rate is 1 job/2 hours. So we can write the equation 1/2 = A + R, using the fact that time is inversely proportional to work rate.
Substituting the value of A from the first equation, we have 1/2 = (R - 3) + R. Solving this equation will give us the value of R, which represents how long it will take Resty to paint the room when he works alone.