Aptitude - Chain Rule - Discussion

Discussion Forum : Chain Rule - General Questions (Q.No. 6)
6.
A man completes of a job in 10 days. At this rate, how many more days will it takes him to finish the job?
5
6
7
7 1
2
Answer: Option
Explanation:

Work done = 5
8

Balance work = 1 - 5 = 3
8 8

Let the required number of days be x.

Then, 5 : 3 = :: 10 : x     5 x x = 3 x 10
8 8 8 8

x = 3 x 10 x 8
8 5

x = 6.

Discussion:
36 comments Page 2 of 4.

Ram said:   8 years ago
Look another eg;

1/2 work = 5 day
Then,
Getting completed ie,
LHS should be 1.
cross multiply.
ie
1=2*5.
=10days.
Similarly,
5/8=10.
1= 8/5*10.
= 16.

Sowmiya said:   8 years ago
Very nice explanation @Bhadra.

Shubham said:   7 years ago
A garrison of 750 men has provision for 20 weeks if, at the end of 4 weeks, they are reinforced by 450 men, how long the provision will last?

How to solve this by using the chain rule? Please help me.

Kathik said:   10 years ago
Given that 5/8 (job) = 10 days.

Then for full job completion take:

1(job) = 10(8/5).

= 16 days.

So in question asked how many remaining days to finish the job.

So Total days - Given days.

= 16 - 10 = 6 days.

Pujan Das said:   6 years ago
5/8 is completed in 10 days.
Hence, 1 (100%) will be completed in (10*8)/5 = 16 days.
The rate of work remains constant. (important point).
Thus, Remaining days = total days - elapsed = 16 - 10 = 6 days.

Jefferson said:   6 years ago
5/8 of the work is completed in 10 days.
So we get the remaining work = (1-5/8).
= 3/8.
Completing work is directly proportional to days.

Hence direct proportion where x/y = constant.
Let we take the time taken to complete 3/8 be x.
And therefore = 10/(5/8) = 16,
for 3/8=8x/3,
thus 8x/3=16,
8x = 48,
and x = 6days.

Anushree said:   3 years ago
@All.

Simply;

First of all, we need to divide 5 by 10, the answer will be 0.5/half so we need to draw two lines for each day, for ex ll-1,ll-2 etc.

And after it comes to 5 just continue drawing two lines for a day (so we will do like this- ll-6, ll-7 and ll-8 )

Now we need to see the number of lines we have drawn, that is 6, then the answer will be 6.

Thank you.

Chandan said:   2 months ago
He completes 5/8 of the work in 10 days.
He can complete the work in,
8/5 * 10 days,
= 80/5 days.
= 16 days.

He completed 10 days of work.
16 - 10 = 6 days.

Chalam said:   1 decade ago
Bhadra & Avijeet,

Nice explanations.

Thanks

Shaunak said:   1 decade ago
Take the problem in the following way:.

A man can complete 5/8 of a work in 10 days. How long does it take to complete 3/8 of the same work?


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