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 6 of 10.
Piyus said:
1 decade ago
Friends
P's 2 hr work = 1/8*2=1/4
rest 3/4 work done by q&r
q+r 1hr = 1/10 + 1/12=11/60 work
3/4 work by q&r=60/11 * 3/4=4.09
The work complete time was 9a.m+4=1p.m
P's 2 hr work = 1/8*2=1/4
rest 3/4 work done by q&r
q+r 1hr = 1/10 + 1/12=11/60 work
3/4 work by q&r=60/11 * 3/4=4.09
The work complete time was 9a.m+4=1p.m
Ramkumar said:
1 decade ago
Can anyone tell
Why you put last step as 9am+4?
Already p, q, r done by 2hrs and (q&r) in 4 hrs know.
Then 2+4=6 only know.
On this step I am in confusion. Help me.
Why you put last step as 9am+4?
Already p, q, r done by 2hrs and (q&r) in 4 hrs know.
Then 2+4=6 only know.
On this step I am in confusion. Help me.
Rahul said:
1 decade ago
All the machines are started at once.
we have got the solution as 4 hrs for both machines q & r
they have started at 9 a.m.
q & r work for 4 hrs
So 9+4=13 i.e,1 p.m.
we have got the solution as 4 hrs for both machines q & r
they have started at 9 a.m.
q & r work for 4 hrs
So 9+4=13 i.e,1 p.m.
Shekar said:
1 decade ago
2(1/8+1/10+1/12)+x(1/10+1/12)=1 we get x value is 2.09. required value is 11am+209=1.09pm,we taken approx value 1pm.
Nav Raj Bhatta said:
4 years ago
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 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.
Parveen said:
1 decade ago
Printing Pages in one hour:
P---->12500
Q---->10000
R---->8333
Because p will be closed at 11 A.M so printed pages by P till 11 A.M (12500*2)= 25000
Remaining pages(100000-25000)= 75000
So time taken will be 75000/(10000+8333)= 4 hours(approx.)
9 A.M+ 4 hours= 1.00P.M
P---->12500
Q---->10000
R---->8333
Because p will be closed at 11 A.M so printed pages by P till 11 A.M (12500*2)= 25000
Remaining pages(100000-25000)= 75000
So time taken will be 75000/(10000+8333)= 4 hours(approx.)
9 A.M+ 4 hours= 1.00P.M
Swedha said:
8 years ago
P=8hours..which implies 2hours=P/4 ie q fourth(0.25) of the work is done by p in 2 hours. Q=10 hours.
Therefore Q's 2 hours work is 0.2. Similarly R's 2 hours work is 0.16
Therefore 2 hours work is 0.25+0.2+0.16=0.616
Remaining work to be done=1-0.616=0.3833
Q+R 1hr work= 1/10+1/12=11/60=0.1833
Next 1 hr work=0.1833
0.1833+0.1833=0.3666.
11+2 hours= 1 pm.
Therefore Q's 2 hours work is 0.2. Similarly R's 2 hours work is 0.16
Therefore 2 hours work is 0.25+0.2+0.16=0.616
Remaining work to be done=1-0.616=0.3833
Q+R 1hr work= 1/10+1/12=11/60=0.1833
Next 1 hr work=0.1833
0.1833+0.1833=0.3666.
11+2 hours= 1 pm.
Ajay said:
1 decade ago
Hi I have 1 short cut to this type of problem.
a,b,c have 2hrs time diffrnce,a completed the work at 11am similarly b at 13 and c at 15. So avg of 11, 13, 15 is 13 i.e., 1.00 pm.
a,b,c have 2hrs time diffrnce,a completed the work at 11am similarly b at 13 and c at 15. So avg of 11, 13, 15 is 13 i.e., 1.00 pm.
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.
Ashna said:
1 decade ago
P in 1 hr-----1/8.
Q in 1 hr-----1/10.
R in 1 hr-----1/12.
Therefore 2/8+(x+2)/10+(x+2)/12 = 1.
On solving x=23/11=2 hrs. (approx).
Therefore, 11 A.M.+2hr = 1 P.M.
Q in 1 hr-----1/10.
R in 1 hr-----1/12.
Therefore 2/8+(x+2)/10+(x+2)/12 = 1.
On solving x=23/11=2 hrs. (approx).
Therefore, 11 A.M.+2hr = 1 P.M.
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