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 21 of 23.
Harshal said:
4 years ago
First A=12.
and B=20.
Now the lcm of A and B is 60.
than A and B one day work is 7 and he's work together 7*4=28.
now the 28/60 forestation is 7*15.
and renaming work - total work 28-60=32.
Now 32/60= forestation us 8/15 answer.
and B=20.
Now the lcm of A and B is 60.
than A and B one day work is 7 and he's work together 7*4=28.
now the 28/60 forestation is 7*15.
and renaming work - total work 28-60=32.
Now 32/60= forestation us 8/15 answer.
Sangmesh said:
4 years ago
5/48 how this came? Please explain.
(1)
Teja said:
3 years ago
A = 16
B = 12.
A + B + C = 4.
16,12,4 LCM = 48.
then,16/48 = 3.
12/48 = 4.
4/48 = 12.
Then,C - (A + B) = 12-(3+4) = 5.
then 48/5.
B = 12.
A + B + C = 4.
16,12,4 LCM = 48.
then,16/48 = 3.
12/48 = 4.
4/48 = 12.
Then,C - (A + B) = 12-(3+4) = 5.
then 48/5.
(5)
Deekshit said:
3 years ago
Why the fraction 5/48 is changed to 48/5? Please explain.
Nil said:
3 years ago
How 48/5 is written as 9*3/5? Please explain.
(1)
Dibyanshu said:
3 years ago
The work is completed by A in 16 days and by B in 12.
LCM of 16 and 12 is 48.(Total work is also 48).
The efficiency of A= 48/16=3 and B= 48/12=4,
They complete the work in 4 days.
Total work/time = Efficiency.
48/4 = 12(Efficiency of A+B+C = 12).
The efficiency of A+B is 3+4=7
The efficiency of C is 12 - 7 = 5.
Total work/Efficiency = Time.
48/5 = 9.6 is also written as (9*3/5).
LCM of 16 and 12 is 48.(Total work is also 48).
The efficiency of A= 48/16=3 and B= 48/12=4,
They complete the work in 4 days.
Total work/time = Efficiency.
48/4 = 12(Efficiency of A+B+C = 12).
The efficiency of A+B is 3+4=7
The efficiency of C is 12 - 7 = 5.
Total work/Efficiency = Time.
48/5 = 9.6 is also written as (9*3/5).
(10)
Dibyanshu said:
3 years ago
@Nil.
It's a fractional rule.
48/5 = 9+3/5.
Let me explain.
=> 5x9 = 45
So, you can say the reminder a numerator and the denominator is also a denominator.
The reminder is 3 and the Denominator is 5.
So, 9*3/5..
It's a fractional rule.
48/5 = 9+3/5.
Let me explain.
=> 5x9 = 45
So, you can say the reminder a numerator and the denominator is also a denominator.
The reminder is 3 and the Denominator is 5.
So, 9*3/5..
(6)
Vaishnavi Deshpande said:
3 years ago
Why do not we consider work done by A+B in 4 days and then subtract it from 1 to get work done by C in 4 days? Please anyone explain me.
(2)
Rickykerketta said:
3 years ago
A --- 15.
B --- 20.
We took LCM -- 60.
15 * 4 = 60.
20 * 3 = 60.
Work done = 4 days * 7 = 28 units of work.
60 - 28 = 32,
Part left = 32/60,
8/32.
B --- 20.
We took LCM -- 60.
15 * 4 = 60.
20 * 3 = 60.
Work done = 4 days * 7 = 28 units of work.
60 - 28 = 32,
Part left = 32/60,
8/32.
(5)
A SANTHI said:
3 years ago
A - 16 Days.
B - 12 days.
A + B + C - 4 days.
We know A and B's one day work - 1/16 and 1/12.
Therefore, Add A+B = 1/16+1/12 (Take LCM).
= 7/48( Which is the one day work for A+B).
We know A+B+C's one-day work = 1/4.
So, A+B+C= 1/4,
7/48+C= 1/4, ( A+B= 7/48 )
C= 1/4 - 7/48 (Take LCM).
C= 5/48 (One day work).
Therefore C's Work = 48/5 (Just inverse of one day),
C= 9 * 3/5.
B - 12 days.
A + B + C - 4 days.
We know A and B's one day work - 1/16 and 1/12.
Therefore, Add A+B = 1/16+1/12 (Take LCM).
= 7/48( Which is the one day work for A+B).
We know A+B+C's one-day work = 1/4.
So, A+B+C= 1/4,
7/48+C= 1/4, ( A+B= 7/48 )
C= 1/4 - 7/48 (Take LCM).
C= 5/48 (One day work).
Therefore C's Work = 48/5 (Just inverse of one day),
C= 9 * 3/5.
(20)
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