Answer:
Time taken by both is 3 hours and 44 minutes.
Explanation:
Working alone, Irina can paint a certain room in = 8 hours
Working alone, Paulo can paint the same room in = 7 hours
Let the time required when they work together be = t
Let the completed job be = 1
Both will do a fraction of the job and the two fractions add up to 1.
Equation becomes:

Now solving this we get


t= 3.73 hours
This becomes 3 hours and 0.73(60)=43.8 ≈ 44 minutes.
Therefore, time taken by both Irina and Paulo is 3 hours and 44 minutes.