A factory with 3 machines has a job of stamping out a number of pan covers. The newest machine can do the job in 3 days, another machine can do it in 4 days, and the third machine can do it in 6 days. How many days will the factory take to do the job using all three machines?

Mutual Trust Bank Ltd Mutual Trust Bank ltd - Probationary Officer - 2016 গণিত ঐকিক নিয়ম (Unitary method) 2016