Aptitude - Time and Work - Discussion

Work from 9 AM to 11 AM,
=> P+Q+R = (1/8+1/10+1/12) * 2.
=> P+Q+R = 37/60.

After 11 AM only Q & R works, So
=> Q+R = 1/10+1/12.
=> Q+R = 11/60 , this is 1 hour work.

As we know if the total work is done it will be 1.

Now predict the hours,
(37/60)+(11/60)+(11/60) => approx 1.
(2) + (1) + (1) => 4 hours.

From (9+4) AM ->> 1 PM.

Total work needs to be completed = lcm (8,10,12) = 120 work.
Efficiency of P (work completed in 1 hr) = 120/8=15 work.
Similarly for Q=12 work and for R = 10.
Total work done by all the three in 1 hr =15+12+10 =37.
From 9 to 11 am all worked together ie. 37*2 =75 work completed out of 120.
Remaining work =120-75 = 45.
Work completed by Q and R in 1 hr = 10+12 =22.
Time taken to complete 45 work ==> 45/22 ~ 2 hrs.
ie.11 AM + 2 hrs ==> Around 1 PM work will be finished.

I think we can do like this!

We need to find (Q+R) Work ! Since, We can write it as,
(Q+R ) = (P+Q+R ) - P ---> 1.

Therefore , P+Q+R = (1/8)+(1/10)+(1/12) = 37/120.
All of them Printed for 2 hrs, So (37/160) * 2 = 37/60.
Now find the Individual Work done by P,
P= (1/8), for 2 hrs (1/8)*2 = 1/4.
1--> (Q+R) = (37/60) - (1/4) = 11/30.

Therefore Taking, 30/11 = (approximately 2 hrs).
11 hrs + 2 hrs = 1 PM.

I hope this will be Easy to Understand!

@All.

The solution is;

P Q R together work for 2 hrs

P + Q + R = 37 *2 = 74,
120-74 = 46.

Remaining 46 works done by Q and R so;

46/22.
23/11 ------ 2 1/11 hours approximately 2 hours.

So, from 11 Am +2 hrs = 1 Pm.

The solution is;

10 - 8=2
12 - 10=2
So, two is a common difference.
Then, P is closed at 11:AM.
11:00 + 00:30 = 11:30.
Continued for four good times then you'll get 1:00PM.

8,10,12 for this lcm 120

Assume 120 books print
Machines printing per hour
P 120/8 = 15
Q 120/10=12
R 120/12=10.

Per hour 3 machine together print books 37

Start 9 am 11 pm machine p stop the work.

2 hours all machine worked so 2 *37=74.

120-74=46 machine Q R together print in one hour 10+12=22.

So 46/22 =2.02 so 2 hours required to print remains books
After 11 am need 2 hours need so answer 1 pm.

Take lcm of 8, 10'12.

Lcm = 120 units book to be printed.
P = 120/8 = 15 units/ hour.
Q = 120/10 = 12 units per hour.
R = 120/12 = 10 units per hour.

Total units per hour=15+12+10=37 units per hour.

P+q+r work together for two hour=37*2=74 units for two hours.

Remaining work=120-72=46 units.

P and R one hour efficiency=12+10=22 units per hour.
They need how much time to finish 46 units?

46/22 = 2.09 hours.

After 11 am they need 2 hours means 1 pm approximately.

This problem is simple;

First, see the difference between the machine completed work it's approximately 2 hours in each machine.

So, p machine end it's work is 11 am so,
The difference is 2.
So simply add that 11+2= 1 pm.

Here,

P take a time to complete the work = 8 hours.
Q take the time to complete the work =10 hours,
R take the time to complete the work=12 hours,
One hour work by PQR=15+10+12 = 37.
Now LCM =120(total unit to complete) (120 unit means 100000).

Now time taken to complete 120 unit = 37*2 (9-11)+22 (11-12)+22(12-13)=120 unit completed till 1 AM.

P - 8 d
Q - 10 d
R - 12 d -------now,LCM of p,q,r is 120.

So, P's one day hour work = 15.
Q's =12
R's. =10.

P works for 2 hours.
So, 2*15=30.
120-30=90.

Remaining work is done by Q and R = 90/22 = 4(approx).
9:00 AM + 4 hrs = 1:00 PM.