Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 14)
14.
P can complete a work in 12 days working 8 hours a day. Q can complete the same work in 8 days working 10 hours a day. If both P and Q work together, working 8 hours a day, in how many days can they complete the work?
Answer: Option
Explanation:
P can complete the work in (12 x 8) hrs. = 96 hrs.
Q can complete the work in (8 x 10) hrs. = 80 hrs.
 P's1 hour's work = |
1 | and Q's 1 hour's work = | 1 | . |
| 96 | 80 |
| (P + Q)'s 1 hour's work = |  |
1 | + | 1 |  |
= | 11 | . |
| 96 | 80 | 480 |
| So, both P and Q will finish the work in | |
480 | |
hrs. |
| 11 |
| Number of days of 8 hours each = |
|
480 | x | 1 | |
= | 60 | days = 5 | 5 | days. |
| 11 | 8 | 11 | 11 |
Discussion:
57 comments Page 5 of 6.
Sikha said:
1 decade ago
Why multipled by 1/8 not 8?
Shekha said:
1 decade ago
Sagarika your explanation is very simple. And Rani maria thanks for thinking me simple.
Shridhar said:
1 decade ago
Sagarika your explaination is very nice.
Sagarika said:
1 decade ago
We can do this by taking up the lcm of both's working hours to complete the task i.e., of 96 and 80 which comes to be 480.
So if the whole work is considered to be 480parts then P can complete in 480/96=5 days and Q can in 480/80=6 days and if they work together then 480/(5+6) days.
If they work 8 hours each then
=(480/11*1/8) days
= 480/88
= 5.454545.. or 5(5/11)
So if the whole work is considered to be 480parts then P can complete in 480/96=5 days and Q can in 480/80=6 days and if they work together then 480/(5+6) days.
If they work 8 hours each then
=(480/11*1/8) days
= 480/88
= 5.454545.. or 5(5/11)
Akila said:
1 decade ago
11/480 is the part of work completed in 1 hour.
If we reverse it we can get time.
If we reverse it we can get time.
Srikanth said:
1 decade ago
Why should we take 11/480 as 480/11 ?
SrinivasaReddy said:
1 decade ago
P can do the work in 12days. He do per day 8 hours.
P can do work in total hours is:96.
Same as Q can do work in:80hours.
P's one day work is:1/96.
Q's one day work is:1/80.
P+q one day work is:1/96+1/80=11/480.
P+q work is:480/11.
P+q can done 8 hours per day:480/11*1/8.
P can do work in total hours is:96.
Same as Q can do work in:80hours.
P's one day work is:1/96.
Q's one day work is:1/80.
P+q one day work is:1/96+1/80=11/480.
P+q work is:480/11.
P+q can done 8 hours per day:480/11*1/8.
Supriya said:
1 decade ago
How can we solve this 480/11 * 1/8..and how came the ans 60/11 ?
Chintan said:
1 decade ago
Neha. . They work to gather 8 hours in 1 day that is shown in que. So ans mult. By 1/8
Rani Maria said:
1 decade ago
Take the LCM of 96,80 then we get 480.
then 1/96 * 480 + 1/80 *480 = 5/480 + 6/480 = 11/480.
then 1/96 * 480 + 1/80 *480 = 5/480 + 6/480 = 11/480.
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