Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 2)
2.
A can lay railway track between two given stations in 16 days and B can do the same job in 12 days. With help of C, they did the job in 4 days only. Then, C alone can do the job in:
Answer: Option
Explanation:
| (A + B + C)'s 1 day's work = | 1 | , |
| 4 |
| A's 1 day's work = | 1 | , |
| 16 |
| B's 1 day's work = | 1 | . |
| 12 |
 C's 1 day's work = |
1 | - |  |
1 | + | 1 |  |
= | |
1 | - | 7 | |
= | 5 | . |
| 4 | 16 | 12 | 4 | 48 | 48 |
| So, C alone can do the work in | 48 | = 9 | 3 | days. |
| 5 | 5 |
Discussion:
226 comments Page 5 of 23.
Cherry said:
5 years ago
Good explanation, Thanks @Billal Hossain.
Billal Hossain said:
5 years ago
Solution:
Let, C did the job in= x days.
ATQ,
1/16+ 1/12+ 1/x = 1/4.
=> 1/x= 1/4- 1/16-1/12,
=> 1/x= (12-3-4)/48,
=> 1/x= 5/48,
=> x= 48/5,
=> x = 9 (3/5).
C alone can do the job in 9(3/5) days.
Let, C did the job in= x days.
ATQ,
1/16+ 1/12+ 1/x = 1/4.
=> 1/x= 1/4- 1/16-1/12,
=> 1/x= (12-3-4)/48,
=> 1/x= 5/48,
=> x= 48/5,
=> x = 9 (3/5).
C alone can do the job in 9(3/5) days.
Sonu singh said:
5 years ago
Thanks all for explaining.
Vignesh said:
6 years ago
@Neha.
It is 48/5=> 45+3/5 = 9 * 3/5.
It is 48/5=> 45+3/5 = 9 * 3/5.
Neha k. said:
6 years ago
I can't understand 9 3/5 last answer.
Anup said:
6 years ago
16,12,4 of lcm=48.
16/48=3.
12/28=4.
4/48=12.
So, total works efficiency =12-7=5 per days;
48/5 is the answer.
16/48=3.
12/28=4.
4/48=12.
So, total works efficiency =12-7=5 per days;
48/5 is the answer.
Sindhu said:
6 years ago
@Bhimesh.
Yes, you are correct.
Yes, you are correct.
Bhimesh said:
6 years ago
Why 5/48 is 48/5 because A can do work in 16 days so his efficiency for 1 day is 1/16.
(which means (work/time)). So same for C's 1-day work is 5/48 and he can complete the work in 48/5.
(which means (work/time)). So same for C's 1-day work is 5/48 and he can complete the work in 48/5.
Shirisha said:
6 years ago
@Sai Kumar.
It is 1÷16 + 1÷12 so 1st do LCM of 16,12 then you'll get the answer as 48 later on divide (48÷16, 48÷12) then you'll get answers as 3 and 4 (as multiplied by the numerator 1 then 3*1 will be 3 and 4*1 will be 4) add 3+4 you'll get 7 then the final answer will be 7/48
It is 1÷16 + 1÷12 so 1st do LCM of 16,12 then you'll get the answer as 48 later on divide (48÷16, 48÷12) then you'll get answers as 3 and 4 (as multiplied by the numerator 1 then 3*1 will be 3 and 4*1 will be 4) add 3+4 you'll get 7 then the final answer will be 7/48
Sai Kumar said:
6 years ago
1/4- (1/16+1/12) = (1/4-7/48) please anyone explain this.
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