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:
96 comments Page 10 of 10.
K.anusha said:
1 decade ago
Please I can't get the answer this last step please friends will explain to me.
How will come to this is 3/4 can you explain to me friends please.
How will come to this is 3/4 can you explain to me friends please.
Hariteja said:
1 decade ago
Hey guys I used a logic mite be correct or not I don't know!
As we know p works for 8hrs, q works for 10hrs and are works for 12hrs so there is difference of 2hrs. Where p complete the works for only 2hrs in time 9am to 11am. In the same time the remaining q and are also works but we observe by comparing q works more than 2hrs so if the q started at the same time where p started then q finish the work at 11am but where as are who work for 4hrs more than p. So in the time of he started he also completes the work at 11am but remaining 2hrs he need to work so the work will be finished at 1pm i.e. (11am+2hrs).
As we know p works for 8hrs, q works for 10hrs and are works for 12hrs so there is difference of 2hrs. Where p complete the works for only 2hrs in time 9am to 11am. In the same time the remaining q and are also works but we observe by comparing q works more than 2hrs so if the q started at the same time where p started then q finish the work at 11am but where as are who work for 4hrs more than p. So in the time of he started he also completes the work at 11am but remaining 2hrs he need to work so the work will be finished at 1pm i.e. (11am+2hrs).
Ranjeet singh said:
1 decade ago
A+B+C = 3/25.
A+A = 3/25 //B+C = A.
2A = 3/25.
A = 3/25*2.
A = 3/50.
A+A = 3/25 //B+C = A.
2A = 3/25.
A = 3/25*2.
A = 3/50.
Shobith said:
1 decade ago
That total of "1" represents the one day.
In the step 2*1/8+(1/80)*x+(1/12)x = 1.
Right @Sameer.
In the step 2*1/8+(1/80)*x+(1/12)x = 1.
Right @Sameer.
Sini said:
1 decade ago
Written by @Sameer:
P 1hrs work 1/8.
Q 1hrs work 1/10.
R 1hrs work 1/12.
p worked for 2 hrs so 2*1/8.
Suppose Q and r worked for 'x' hrs.
then,
2*1/8+(1/10)*x+(1/12)x = 1.
x=4.09.
Ans 9+4.09 = 1pm.
Sameer, How do we get the step 2*1/8+(1/10)*x+(1/12)x = 1.
i.e how is the total equal to 1?
P 1hrs work 1/8.
Q 1hrs work 1/10.
R 1hrs work 1/12.
p worked for 2 hrs so 2*1/8.
Suppose Q and r worked for 'x' hrs.
then,
2*1/8+(1/10)*x+(1/12)x = 1.
x=4.09.
Ans 9+4.09 = 1pm.
Sameer, How do we get the step 2*1/8+(1/10)*x+(1/12)x = 1.
i.e how is the total equal to 1?
SANJEEV said:
1 decade ago
2(1/8)+x(1/10 + 1/12) = 1.
>> x=45/11 nearly 4 >> 1pm.
>> x=45/11 nearly 4 >> 1pm.
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