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 5 of 10.
Parkavi said:
5 years ago
@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;
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.
Kumar said:
1 decade ago
@sneha Its just taking Lcm for 1/8+1/10+1/12 you il get 37/120.
Lcm for 8, 10, 12 is 120.
8 goes 15 times in 120 and 10 goes 12 times in 120 and 12 goes 10 times in 120.
By adding 15+10+12=37 you will get.
Hope you got it.
Lcm for 8, 10, 12 is 120.
8 goes 15 times in 120 and 10 goes 12 times in 120 and 12 goes 10 times in 120.
By adding 15+10+12=37 you will get.
Hope you got it.
Baji said:
4 years ago
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.
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.
(13)
Kumar said:
1 decade ago
@vachu P is working for 2 hrs it is mentioned indirectly.
In question they told all machines started at 9 am and p closed at 11 am means p's Time is 9-10 1 hour and 10-11 2 hrs Total p's machine Time is 2 Hours Right.
In question they told all machines started at 9 am and p closed at 11 am means p's Time is 9-10 1 hour and 10-11 2 hrs Total p's machine Time is 2 Hours Right.
Kranthi said:
8 years ago
P can work 2 hours 2/8 = 1/4.
We don't know how much Q and R work so let be think as = x.
1/4 + x/10 + x/12 =1.
LCM 60.
15+6x+5x=60,
15+11x=60,
11x=45,
X=4.~.
Work started at 9 so add 4 hours = 9+4 = 13 (1P.M).
We don't know how much Q and R work so let be think as = x.
1/4 + x/10 + x/12 =1.
LCM 60.
15+6x+5x=60,
15+11x=60,
11x=45,
X=4.~.
Work started at 9 so add 4 hours = 9+4 = 13 (1P.M).
Harini Murali said:
3 months 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.
(7)
Divya said:
2 years ago
P=80,
Q=10,
R=12.
L.C.M = 120
P=15,Q = 12,R = 10
For 2 hours = 2*15+12+10 = 27units
The remaining 66 units are (Q+R)
Q+R = 12+10 = 22
Q+R = 66/22 = 3hours
11 A.M + 3hours = 1 P.M.
Q=10,
R=12.
L.C.M = 120
P=15,Q = 12,R = 10
For 2 hours = 2*15+12+10 = 27units
The remaining 66 units are (Q+R)
Q+R = 12+10 = 22
Q+R = 66/22 = 3hours
11 A.M + 3hours = 1 P.M.
(22)
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.
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.
Zoya said:
1 decade ago
Why we multiplying total time (x) by 1/8, 1/10, 1/12?
Why here we doing x/8+1/10+1/12?
Is there any formula like total time/work done?
Please anyone help me for this method.
Why here we doing x/8+1/10+1/12?
Is there any formula like total time/work done?
Please anyone help me for this method.
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