Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 10)
10.
A machine P can print one lakh books in 8 hours, machine Q can print the same number of books in 10 hours while machine R can print them in 12 hours. All the machines are started at 9 A.M. while machine P is closed at 11 A.M. and the remaining two machines complete work. Approximately at what time will the work (to print one lakh books) be finished ?
Answer: Option
Explanation:
| (P + Q + R)'s 1 hour's work = |  |
1 | + | 1 | + | 1 |  |
= | 37 | . |
| 8 | 10 | 12 | 120 |
| Work done by P, Q and R in 2 hours = | |
37 | x 2 | |
= | 37 | . |
| 120 | 60 |
| Remaining work = | |
1 - | 37 | |
= | 23 | . |
| 60 | 60 |
| (Q + R)'s 1 hour's work = | |
1 | + | 1 | |
= | 11 | . |
| 10 | 12 | 60 |
| Now, | 11 | work is done by Q and R in 1 hour. |
| 60 |
| So, | 23 | work will be done by Q and R in | |
60 | x | 23 | |
= | 23 | hours  2 hours. |
| 60 | 11 | 60 | 11 |
So, the work will be finished approximately 2 hours after 11 A.M., i.e., around 1 P.M.
Discussion:
95 comments Page 2 of 10.
Joel said:
4 years ago
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.
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.
(8)
Aaren said:
1 year ago
@All.
According to me, the Time taken for P, Q, R machines together to print everything will be 120/37 ~3.5 hours or about 12:30 pm.
So, if one machine stops working in between then obviously it will take more time than 12:30 and there was only one option satisfying this condition.
Anyone, please clarify this to me clearly.
According to me, the Time taken for P, Q, R machines together to print everything will be 120/37 ~3.5 hours or about 12:30 pm.
So, if one machine stops working in between then obviously it will take more time than 12:30 and there was only one option satisfying this condition.
Anyone, please clarify this to me clearly.
(8)
Harini Murali said:
3 weeks ago
P - 1,00,000 = 8H.
Q - 1,00,000 = 10H.
R - 1,00,000 = 12H.
P, Q, R start at 9.00AM,
P = 11.00AM finished,
R - P = 2H.
Total 2 hrs difference,
11.00AM + 2 = 1:00 PM.
Then Ans : 1.00pm.
Q - 1,00,000 = 10H.
R - 1,00,000 = 12H.
P, Q, R start at 9.00AM,
P = 11.00AM finished,
R - P = 2H.
Total 2 hrs difference,
11.00AM + 2 = 1:00 PM.
Then Ans : 1.00pm.
(3)
PADAMATA PAVAN KUMAR said:
1 year ago
Total unit of work is 240 units.p done per hour 30 units and q done 24 units and r done 20 units per hour.
Now three worked per 2 hr i.e 2(30×24×20)=148 units, remaining=240-148=92 units.
Now p left so only q and r can do in 1 hr (24+20)=44 units .
If they both worked for 2hr.
i.e 44×2=88 units then the total work will finish here 92approx 88,
So, take 2 hr 11 to 2 hr means 1 P.M.
Now three worked per 2 hr i.e 2(30×24×20)=148 units, remaining=240-148=92 units.
Now p left so only q and r can do in 1 hr (24+20)=44 units .
If they both worked for 2hr.
i.e 44×2=88 units then the total work will finish here 92approx 88,
So, take 2 hr 11 to 2 hr means 1 P.M.
(3)
Rojash thapa said:
3 years ago
Please somebody help me to solve this problem in an easy way.
(2)
Keval shah said:
1 year ago
Thanks for the explanation @Sai Vinitha.
(2)
Sukanya said:
9 years ago
The difference between every machine is two hours, so 2hr + 11hr = 13 hrs, ie 1:00 clock.
(2)
Parthiban said:
5 years ago
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.
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.
(2)
Tanmay chahande said:
5 years ago
See,
P works for 8 hours.
Q works for 10 hours.
R works for 12 hours.
The total time taken by the three machines is 30 hours that is 1 day and 6 hours.
Next condition says that three machines start at 9,00 am and p stops in 2 hours means machines worked for 1 Day and 4 hours now when we calculate 1 day 4 hours from 9.00 am we get clock time 1.00 pm.
P works for 8 hours.
Q works for 10 hours.
R works for 12 hours.
The total time taken by the three machines is 30 hours that is 1 day and 6 hours.
Next condition says that three machines start at 9,00 am and p stops in 2 hours means machines worked for 1 Day and 4 hours now when we calculate 1 day 4 hours from 9.00 am we get clock time 1.00 pm.
(2)
Barshan Roy said:
5 months ago
Well explained. Thanks all.
(1)
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