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:
58 comments Page 3 of 6.
Ash said:
9 years ago
Why 12*8 is taken? 12 days n 8 hrs =96hrs how it comes?
Please explain it.
Please explain it.
Amritha said:
9 years ago
@Ash
For 1 day P works for 8hours, then for 12 days (Since P completes the work in 12days.), the total no of hours is 96 hours(12 * 8).
For 1 day P works for 8hours, then for 12 days (Since P completes the work in 12days.), the total no of hours is 96 hours(12 * 8).
Akila said:
2 decades 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.
Singham said:
8 years ago
If the equation is multiple with 1/8, then how could be possible that the is 5*5/11?
Supriya said:
8 years ago
We should take as 1/12 that means 1/n for every question noo. But in this question why we have taken as 12*8, why can't 1/12*8?
Anyone explain me.
Anyone explain me.
Nagesh G S said:
1 decade ago
The total amount work done is 480/11, but we can not divide it by 8. Because P works for 8 hours a day and Q works for 10 hours a day.
Instead we have to calculate the amount of work done by P per day + amount of work done by Q per day, The take the reciprocal.
If we do that we get:
P = 1/96*8 = 1/12 units of work per day.
Q = 1/80*10 = 1/8 units of work per day.
Amount of work done By P+Q per day = 1/8 + 1/12 = 5/24.
Therefore to complete the entire work it will take 24/5 days.
That's equal to 4 4/5 days.
Instead we have to calculate the amount of work done by P per day + amount of work done by Q per day, The take the reciprocal.
If we do that we get:
P = 1/96*8 = 1/12 units of work per day.
Q = 1/80*10 = 1/8 units of work per day.
Amount of work done By P+Q per day = 1/8 + 1/12 = 5/24.
Therefore to complete the entire work it will take 24/5 days.
That's equal to 4 4/5 days.
SrinivasaReddy said:
2 decades 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:
2 decades ago
How can we solve this 480/11 * 1/8..and how came the ans 60/11 ?
Chintan said:
2 decades 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:
2 decades 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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