Lavesh can paint a a house in just 3 hours.However it takes 6 hours for vishesh to complete the same job.

How long would it take for both to complete the same job?

two hours.

lavesh who could complete the job in 3 hours could complete 2/3 of the job in two hours. Vishesh who complete the job in 6 hours could complete 1/3 of the job in two hours.

2/3 + 1/3 = 1.