A man can do a job in 15 days. his father takes 20 days and his son finishes it in 25 days. how long will they take to complete the job if they all work together?
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Answered by
15
(15×20×25)÷(15×20+15×25+25×20)=6(18÷47)or 6.38
Answered by
26
Work done by man in 15 days= 1
Work done by man in 1 day= 1/15
Work done by father in 20 days=1
Work done by father in 1 day= 1/20
Work done by son in 25 days=1
Work done by son in 1 day=1/25
Work done by altogether= Work of man+Work of father+Work of son
= (1/15+1/20+1/25)days
=(20+15+12/300)days
=47/300 days = 6 whole 18/47 days.
BE BRAINLY
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