Aptitude - Chain Rule - Discussion
Discussion Forum : Chain Rule - General Questions (Q.No. 5)
5.
39 persons can repair a road in 12 days, working 5 hours a day. In how many days will 30 persons, working 6 hours a day, complete the work?
Answer: Option
Explanation:
Let the required number of days be x.
Less persons, More days (Indirect Proportion)
More working hours per day, Less days (Indirect Proportion)
| Persons | 30 | : | 39 |  |
:: 12 : x |
| Working hours/day | 6 | : | 5 |
30 x 6 x x = 39 x 5 x 12
 x = |
(39 x 5 x 12) |
| (30 x 6) |
x = 13.
Discussion:
32 comments Page 2 of 4.
Sanjay said:
9 years ago
You have taken this as:
Persons --> 30 : 39 :: 12 : x,
Working hours/day --> 6 : 5,
Why it can't be like,
Persons --> 39 : 30 :: 12 : x,
Working hours/day --> 5 : 6,
So, I get the equation as (39 * 5 * x) = (30 * 6 * 12).
Persons --> 30 : 39 :: 12 : x,
Working hours/day --> 6 : 5,
Why it can't be like,
Persons --> 39 : 30 :: 12 : x,
Working hours/day --> 5 : 6,
So, I get the equation as (39 * 5 * x) = (30 * 6 * 12).
Miyyapuram said:
1 decade ago
Ny cross multiplication method i didn't get correct ans.....
39---->12*5hrs
then 30---->x*6hrs
Now 30*12*5=39*x*6
then 30*12*5/39*6=x......... then i got 100/13........
is it correct or wrong
39---->12*5hrs
then 30---->x*6hrs
Now 30*12*5=39*x*6
then 30*12*5/39*6=x......... then i got 100/13........
is it correct or wrong
Sachin prakash srivastava said:
1 decade ago
M1D1H1 M2D2H2
------ = ------
W1 W2
Where,
M = No.of Men
D = No.of Days
H = No.of Hours
W = Amt of Work done.
In this problem, if we apply this equation,
39*12*5 = 30*6*x
x=13 is the answer.
------ = ------
W1 W2
Where,
M = No.of Men
D = No.of Days
H = No.of Hours
W = Amt of Work done.
In this problem, if we apply this equation,
39*12*5 = 30*6*x
x=13 is the answer.
Lipu said:
1 decade ago
39 persons can repair in 60 hours.
1 person can do in 60*39 hours.
30 persons can do it in(60*39)/30 hours = 78 hours.
If they work 6 hours a day.
So no.of days is 78/6 = 13 days.
1 person can do in 60*39 hours.
30 persons can do it in(60*39)/30 hours = 78 hours.
If they work 6 hours a day.
So no.of days is 78/6 = 13 days.
Aayush said:
4 years ago
To solve, we need to have at least two scenarios.
Scenario1 Scenario 2
39 * 12 * 5 = 30 * X * 6,
2340 = 180 * X,
2340 ÷ 180 = X,
13 = X.
Scenario1 Scenario 2
39 * 12 * 5 = 30 * X * 6,
2340 = 180 * X,
2340 ÷ 180 = X,
13 = X.
(4)
Santosh k said:
9 years ago
For the first statement Total man hours = 39*12*5.
Again for the second statement man hours = 30*X*6.
Equating both equation X = 39*12*5/30*X*6 = 13 days.
Again for the second statement man hours = 30*X*6.
Equating both equation X = 39*12*5/30*X*6 = 13 days.
Raja said:
1 decade ago
The total number of hours of work is 39(people)*60 (Working 60 hours) = 2340.
Now 30 people working 6 hours so the number of days are 2340/180 = 13.
Now 30 people working 6 hours so the number of days are 2340/180 = 13.
Subhi said:
1 decade ago
I have a question plz answer:
12 men or 15 women completes a piece of work in 66 days, 24 men and 3 women together can complete in in how many days?
12 men or 15 women completes a piece of work in 66 days, 24 men and 3 women together can complete in in how many days?
Mithilesh said:
1 decade ago
1 person can do this work in 39*12*5 = 2340 hrs.
Hence 30 persons will do in 2340/30 = 78 hrs = 78/6 13 days.
I think its very understandable.
Hence 30 persons will do in 2340/30 = 78 hrs = 78/6 13 days.
I think its very understandable.
Jeyan said:
1 decade ago
Ya. Right. Even I got so!
Why not we say 39 persons did work in (12*5) hours.
Then what would be 30 persons working for (x*6) hours ?
Why not we say 39 persons did work in (12*5) hours.
Then what would be 30 persons working for (x*6) hours ?
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