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?
5 5
11
5 6
11
6 5
11
6 6
11
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 3 of 6.

Henry said:   10 years ago
What amount of work are they to complete?

Tuhinaa said:   9 years ago
The explanation is a bit lengthy. Is there any shortcut to solve it.

Bhagyasri said:   8 years ago
1-hour work of p and q is(1/12*8+1/8*10) = 11/480.
8-hours of work is (11/480)*8 = 11/60.
For example, 1 day work is 1/x days then the total number of days is x.
Similarly, 8 hours of work is 11/60 then the total number of days is 60/11.

Hariom pundir said:   8 years ago
25 men take 20 days to finish some work, after every 10 days 5 men leave the work, then in how many days will the work be finished? Explain the answer.

Ash said:   8 years ago
Why 12*8 is taken? 12 days n 8 hrs =96hrs how it comes?

Please explain it.

Deepak Patgar said:   1 decade ago
@Sumasree.

Suppose if A does a work in 8 days, amount of work done by him in 1 day will be 1/8,

Its the reciprocal.
In the same way if both of them does 11/60 work in 1 day they will require 60/11 days to complete that work.

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.

SARAN KUMR said:   4 weeks ago
@Nav Raj Bhatta.

To make it easy to calculate, we can divide both by 8.
Now P = 96/8 = 12,
and Q=80/8=10,

Shridhar said:   1 decade ago
Sagarika your explaination is very nice.


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