Aptitude - Chain Rule - Discussion
Discussion Forum : Chain Rule - General Questions (Q.No. 14)
14.
36 men can complete a piece of work in 18 days. In how many days will 27 men complete the same work?
Answer: Option
Explanation:
Let the required number of days be x.
Less men, More days (Indirect Proportion)
27 : 36 :: 18 : x 
27 x x = 36 x 18
 x = |
36 x 18 |
| 27 |
x = 24.
Discussion:
14 comments Page 2 of 2.
Davinder said:
1 decade ago
please give exoplanation fully.........
i am agree with snehal
i am agree with snehal
Hary said:
1 decade ago
Snehal,.
Here we cannot cross multiply like this.
Because, No of men is inversely proportional to no of days.
So, No of men is directly proportional to 1/no of days.
We should write it as.
No of men=k/no of days.
36 = k / 18 ------- (1).
27 = k / ? ------- (2).
Dividing (1) and (2).
36/27 = ?/18.
? = 36*18/27.
No of days = 24.
Here we cannot cross multiply like this.
Because, No of men is inversely proportional to no of days.
So, No of men is directly proportional to 1/no of days.
We should write it as.
No of men=k/no of days.
36 = k / 18 ------- (1).
27 = k / ? ------- (2).
Dividing (1) and (2).
36/27 = ?/18.
? = 36*18/27.
No of days = 24.
Snehal said:
1 decade ago
But if we do it like this,
36 men - 18 days.
27 men - ?.
By cross multiplication, the answer will be different.
36 men - 18 days.
27 men - ?.
By cross multiplication, the answer will be different.
Robert said:
1 decade ago
Give the explanation fully.
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