Question

a can do a piece of work in 15 hours B in 20 hours and C in 30 days if they work together how much time will they need to complete the work ?
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Answer 1

Answer:

251. 6667 hours

Step-by-step explanation:

15+20+720/3

Answer 2

Answer:

6.67 hours

Step-by-step explanation:

a+b+c=> (1/15)+(1/20)+(1/30)

LCM: (9/60)

simply (3/20) this is per hour

inverse : (20/3)

Ans: 6.67 hours