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 18 of 23.
Ammu said:
9 years ago
@Shruti.
A's one day work = 1/16.
B's one day work = 1/12.
with the help of C , they finished in 4 days.
So, A+B+C=4 days,
Therefore, (A+B+C)'s one day work = 1/4.
If C alone is = X.
then 1/16+1/12+X = 1/4,
X= 1/4-(1/16+1/12) {Lcm of 16, 12 is 48 and by the cross multiplication will get 7/48}
= 1/4-7/48,
= 12-7/48,
= 5/48,
C's one day work = 5/48.
A's one day work = 1/16.
B's one day work = 1/12.
with the help of C , they finished in 4 days.
So, A+B+C=4 days,
Therefore, (A+B+C)'s one day work = 1/4.
If C alone is = X.
then 1/16+1/12+X = 1/4,
X= 1/4-(1/16+1/12) {Lcm of 16, 12 is 48 and by the cross multiplication will get 7/48}
= 1/4-7/48,
= 12-7/48,
= 5/48,
C's one day work = 5/48.
Gokul said:
9 years ago
According to me,
a+b+c=4
a=16
b=12
c=?
C = a * b/b-c,
=16 * 12/16-12,
= 16 * 12/4,
=4 * 12 = 48.
Am I correct?
a+b+c=4
a=16
b=12
c=?
C = a * b/b-c,
=16 * 12/16-12,
= 16 * 12/4,
=4 * 12 = 48.
Am I correct?
Jamshed Alam said:
9 years ago
A = 16 Days.
B = 12 Days.
A+B+C = 4 Days.
C = ?
1st of all we take LCM of 16, 12, and 4.
LCM of 16,12 and 4 is 48.
It means whole work is 48 unit then we find the unit of per day of all.
A = 48/16 = 3unit/day.
B = 48/12 = 4unit/day.
A+B+C = 48/4 = 12unit/day.
A+B = 3+4 = 7unit/day.
Now subtract from (A+B+C)-(A+B)=12-7 = 5.
C = 5unit/day.
It means C can alone of whole work is 48/5 days.
B = 12 Days.
A+B+C = 4 Days.
C = ?
1st of all we take LCM of 16, 12, and 4.
LCM of 16,12 and 4 is 48.
It means whole work is 48 unit then we find the unit of per day of all.
A = 48/16 = 3unit/day.
B = 48/12 = 4unit/day.
A+B+C = 48/4 = 12unit/day.
A+B = 3+4 = 7unit/day.
Now subtract from (A+B+C)-(A+B)=12-7 = 5.
C = 5unit/day.
It means C can alone of whole work is 48/5 days.
Ankur said:
9 years ago
How 7/48 come from 1/16+1/12?
Please explain me.
Please explain me.
Vinay said:
8 years ago
A = 1/16.
B = 1/12.
According to Qsn A + B + C = 1/4.
Add A, B values.
Here,
1/16 + 1/12 + C = 1/4,
C = 1/4 - 1/16 - 1/12,
= 5/48.
Total Days of C = 48/5.
B = 1/12.
According to Qsn A + B + C = 1/4.
Add A, B values.
Here,
1/16 + 1/12 + C = 1/4,
C = 1/4 - 1/16 - 1/12,
= 5/48.
Total Days of C = 48/5.
Monu Monika said:
8 years ago
Work is inversely proportional to days 5/48 is the answer for work To convert it into days he changed 5/48 into 48/5.
Shafiyulla said:
8 years ago
Solve my doubt, please.
A+b+c=1/4 correct.
Then how C' s one day work became 1/4?
A+b+c=1/4 correct.
Then how C' s one day work became 1/4?
Sasi said:
8 years ago
A+b+c-(a+b)=1/4-1/16-1/12=1/4(1/1-1/4-1/3).
4*4**3=48.
=>12-7/48=5/48.
4*4**3=48.
=>12-7/48=5/48.
Amit Bhardwaj said:
8 years ago
Thanks, @Ishwar.
Anurag Singh said:
8 years ago
A work = 16 days.
B work = 12 days.
Total work done by A and B = 48 unit (LCM Of A and B).
So work done by A in one day = 48/16= 3 unit.
And work done by B in one day = 48/12 = 4 unit.
So work done by A and B in 1 day = 3+4 = 7 unit.
Work done by A and B in 4 days = 7*4 = 28 unit.
So remaining work = 48-28 = 20 unit.
So work done bye C in one day= 20/4 = 5 unit.
So total work done by C in days = 48/5 days =9*3/5 days.
B work = 12 days.
Total work done by A and B = 48 unit (LCM Of A and B).
So work done by A in one day = 48/16= 3 unit.
And work done by B in one day = 48/12 = 4 unit.
So work done by A and B in 1 day = 3+4 = 7 unit.
Work done by A and B in 4 days = 7*4 = 28 unit.
So remaining work = 48-28 = 20 unit.
So work done bye C in one day= 20/4 = 5 unit.
So total work done by C in days = 48/5 days =9*3/5 days.
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