If X, Y, Z can do a piece of work in 8 days, 12 days and 15 days respectively, how long will they take, if they work together?
Answers
Answer:
X, Y, and Z can do a piece of work in 12 days, 6 days, and 24 days respectively. In what time will they finish if they all do it together?
For this problem we need to calculate the rate at which X, Y and Z get the work done. The rate is the amount of work completed in one day. When they work together the rate of work would add up since they are working together to do a piece of work at the same time.
Rate of work for X = 1/12 (Since X takes 12 days, he would do 1/12 the work in a day). Similarly Rate of work for Y = 1/6 and Rate of work for Z = 1/24.
Add them together we get 1/12+1/6+1/24 = 2+4+1/24 = 7/24. Which means that when they work together they complete 7/24th of the work in a day.
That also means they would take 1/(7/24) days to finish the work or 24/7 days
Answer:
Work done by X in 4 days =(20/1×4)=5/1
Remaining work =(1−51)=5/4
(X+Y)'s 1 day's work =(20/1+12/1)=60/8=15/2
Now, 15/2 is work done by X and Y in 1 day.
So, 5/4 work will be done by X and Y in (21/5×5/4)=6 days.
Hence, total time taken =(6+4) days =10 days.