Question

3. A can do a piece of work in 7 days of 9 hours each and B can do it in 6 days of 7 hours each. How long will they take to do it, working together 8⅖ hrs a day?​

Answer 1

Answer:

They will do it together in 3 days.

Step-by-step explanation:

Total hours in which A will complete them total work is = (7 x 9) hours = 63 hours.

Hence in 1 hour, A can work = (1/63) of total work.

Total hours in which B can complete the work is = (6 x 7) = 42 hours.  

Hence in 1 hour, B can work = (1/42) of total work.

Hence in 1 hour, A and B both can work = (1/63)+(1/42) = (5/126) of total work.

Then the total work will be finished in {1/(5/126)} hours=  (126/5) hours.

Working together 8⅖ hours a day, number of days will be = (126 x 5)/(5 x 42) days = 3 days.