David can finish painting the room in 6 hours, and his elder brother Antony can finish it in 4 hours. If both brothers paint the room together, how many hours will it take them?

Step-by-step explanation:

1/6+1/4=5/12

5/12 of the job is done in 1 hour

so

5/12+5/12 = 10/12

so 10/12 of the job is done in 2 hours

and then simplify 5/6 so then add 1/6

so it is done in 2 hours and 24 minutes