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 6 of 23.
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)
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.
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.
Tom said:
2 years ago
(A-B-C) = 1/16-1/12-1/4.
LCM value = 48.
A = 16*3 = 48 (3).
B = 12*4 = 48 (4).
C = 4*12 = 48 (12) .
So,
A = 3.
B = 4.
C = 12.
Then subtract value. i.e AB-C.
AB = 7, C = 12.
12-7 =5,
Answer 48/5.
Final answer 9*3/5.
LCM value = 48.
A = 16*3 = 48 (3).
B = 12*4 = 48 (4).
C = 4*12 = 48 (12) .
So,
A = 3.
B = 4.
C = 12.
Then subtract value. i.e AB-C.
AB = 7, C = 12.
12-7 =5,
Answer 48/5.
Final answer 9*3/5.
(79)
Anurag said:
1 decade ago
Can anybody explain LCM method like this?
Lets see this simple method,
LCM of 16 and 12 is 48.
So A and B will finish their work in 3 and 4 hr.
Answer C will finish in 12 hr.
Hence 12-(3+4) = 5 hr.
Hence answer is 48/5.
Lets see this simple method,
LCM of 16 and 12 is 48.
So A and B will finish their work in 3 and 4 hr.
Answer C will finish in 12 hr.
Hence 12-(3+4) = 5 hr.
Hence answer is 48/5.
GAUTAM said:
1 decade ago
Answer of C work 5/48 to 48/5.
This is one day work of C.
Example as given in question itself.
A work complete in 16 day so in 1 day 'a' will complete 1/16 portion of whole work. Whole work completed by a is 16/1=16 days.
This is one day work of C.
Example as given in question itself.
A work complete in 16 day so in 1 day 'a' will complete 1/16 portion of whole work. Whole work completed by a is 16/1=16 days.
Ved Prakash Singh said:
8 years ago
A's one day work=1/16.
B's one day work=1/12.
Let C can finish the work in x days hence C's one day work=1/x.
A, B and C together can finish the work in 4 days and total work is 1.
4/16+4/12+4/x=1.
so x=48/5 =>9*3/5.
B's one day work=1/12.
Let C can finish the work in x days hence C's one day work=1/x.
A, B and C together can finish the work in 4 days and total work is 1.
4/16+4/12+4/x=1.
so x=48/5 =>9*3/5.
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.
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)
Manish said:
8 years ago
@ALL.
a&b's work for 4 days=7/12.
bal is c work =1-7/12=5/12.
c's 5/12 work in 4 days.
Therefore- 1 work ie 100 % work in how many days?
5/12 in 4 days.
1 in how many days.
4*12/5=48/5 days.
Fraction= 9*3/5.
a&b's work for 4 days=7/12.
bal is c work =1-7/12=5/12.
c's 5/12 work in 4 days.
Therefore- 1 work ie 100 % work in how many days?
5/12 in 4 days.
1 in how many days.
4*12/5=48/5 days.
Fraction= 9*3/5.
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