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:
224 comments Page 20 of 23.
Sai said:
5 years ago
Answer is 9 3/5 days.
Karthick said:
5 years ago
How did come 5/48? Explain please.
Palem Ganesh said:
5 years ago
It's quite easy, I will tell the shortcut method.
Take LCM of 16 an 12 is 48 and;
Then find one day work as units.
A = 48/16 = 4.
B = 48/12 = 3.
C = ?.
We know they all together they take just 4 days.
Per day of 4 days work = 48/4 = 12.
A + B + C = 12.
4 + 3 + C = 12.
C = 5.
So, C can do work 5 units per day.
C= 48/5.
Take LCM of 16 an 12 is 48 and;
Then find one day work as units.
A = 48/16 = 4.
B = 48/12 = 3.
C = ?.
We know they all together they take just 4 days.
Per day of 4 days work = 48/4 = 12.
A + B + C = 12.
4 + 3 + C = 12.
C = 5.
So, C can do work 5 units per day.
C= 48/5.
Jaya said:
5 years ago
Thank you friends.
Disha said:
4 years ago
5/48 of the whole work is done in one day. Then one whole work is;
5/48:1::1:x.
1*1/[5/48] = 48/5.
5/48:1::1:x.
1*1/[5/48] = 48/5.
Gunjan said:
4 years ago
A-15.
B-20.
1/15 + 1/20 = 7/60.
7/60 x 4= 28/60 = 14/30 = 7/15.
( 1 - 7/15 ) = 8/15.
B-20.
1/15 + 1/20 = 7/60.
7/60 x 4= 28/60 = 14/30 = 7/15.
( 1 - 7/15 ) = 8/15.
Gunjan said:
4 years ago
Agree @Truptimayee Bahinipati.
A=15 days.
B= 20 days.
Then the addition of 1/15 + 1/20 =7/60.
7/60 x 4 = 28/60, 28/60 = 14/30, 14/30 = 7/15.
[ 1- 7/15 ] = 8/15.
Answer = 8/15.
A=15 days.
B= 20 days.
Then the addition of 1/15 + 1/20 =7/60.
7/60 x 4 = 28/60, 28/60 = 14/30, 14/30 = 7/15.
[ 1- 7/15 ] = 8/15.
Answer = 8/15.
Nahida Naaz said:
4 years ago
A -> 16
B -> 12.
Lcm -> 48.
Effi 3 and 4.
4 days work of (A+B) :- 4*7 = 28.
Total work - 4 days work of (A+B).
48- 28= 20.
Remaining work of 'C' will do in 4 days
So , 20/4 = 5.
Hence,
Whole work done by 'C'. 48/5.
B -> 12.
Lcm -> 48.
Effi 3 and 4.
4 days work of (A+B) :- 4*7 = 28.
Total work - 4 days work of (A+B).
48- 28= 20.
Remaining work of 'C' will do in 4 days
So , 20/4 = 5.
Hence,
Whole work done by 'C'. 48/5.
St_osagie said:
4 years ago
@All.
Those asking this question: How did come 5/48?
It is called the "rule of flip in time and work" which is how efficiency in piece is derived. Eg. If it takes 3 days for tom to perform a given task. Tom's efficiency in piece is 1/3.
Those asking this question: How did come 5/48?
It is called the "rule of flip in time and work" which is how efficiency in piece is derived. Eg. If it takes 3 days for tom to perform a given task. Tom's efficiency in piece is 1/3.
(1)
Talib said:
4 years ago
A = 16.
B = 12.
A + B + C = 4.
Total work by a, b, c ie LCM of 16, 12, 4 = 48.
Then A work in 1 day = 48/16 = 3unit.
and B work in 1 day = 48/12 = 4 unit.
And A +B+C work in 1 days = 48/4= 12 unit.
Therefore put value of a and b ie 3 + 4 + c = 12.
ie c work in 1 day = 5 unit.
Therefore total work done by C is 48/5 ans simple and fast method.
B = 12.
A + B + C = 4.
Total work by a, b, c ie LCM of 16, 12, 4 = 48.
Then A work in 1 day = 48/16 = 3unit.
and B work in 1 day = 48/12 = 4 unit.
And A +B+C work in 1 days = 48/4= 12 unit.
Therefore put value of a and b ie 3 + 4 + c = 12.
ie c work in 1 day = 5 unit.
Therefore total work done by C is 48/5 ans simple and fast method.
(3)
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers