P and Q can harvest a field in 5 and 7 days respectively.after P has worked for 3 days, he is joined by Q.in how many more days will the work be completed?
P`s one day work =
Q`s one day work =
Since P worked alone for 3 days,
work completed by P =
Work left =
Now, Q also joined P.
So, work done by them in one day = P`s one day work + Q`s one day work
So, of work is completed in 1 day
so, of work will be completed in
Hence, the work will be completed on the second day when they start working together.
HARVESTING COMPLETED BY P IN 5DAYS
HARVESTING COMPLETED BY Q IN 7 DAYS
SO WORK DONE BY P IN ONE DAY= 1/5
AND Q = 1/7
NOW WORK DONE BY P IN 3 DAYS = 3/5
NOW TOTAL WORK DONE BY THEM IN ONE DAY = 1/5+1/7
SO DAYS NEDDE TO COMPLETE THE HARVEST=35/12 DAYS
AS WE KNOW THAT 3/5 PART OF WORK HAS BEEN ALREADY DONE BY P
SO NOW TIME TAKEN TO COMPLETE THE HARVEST = 35/12 - 3/5
= 139 / 60 DAYS
= 2 19/60 DAYS
SO TIME TAKEN TO COMPLETE THE HARVEST IS 2 19/60 DAYS