Question

A, B and C can do a job in 12 h. 20 h and 30 h respectively. If they all work together, how
long will they take to complete the job?​

Answer 1

Answer:

1 hour work of each of them respectively are

1/12,1/20,2/30

take out its LCM

and then

1-5/60+3/60+2/60

1-10/60

1-1/6

they can do it in 5 hour