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 13 of 23.
Naresh said:
1 decade ago
How do you get 1/4?
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.
Sasmita said:
1 decade ago
Tell me any one that c's work. I can't understand it.
Harmit said:
1 decade ago
Easiest method.
LCM is 48 of 16 &12. Then A can complete work in 3 work and B can 4 work.
Now A B C can complete 12 work.
Now A and B complete 7 work so still remaining work is 5.
So C can alone complete work 48/5. So answer is C. You can easily calculate.
LCM is 48 of 16 &12. Then A can complete work in 3 work and B can 4 work.
Now A B C can complete 12 work.
Now A and B complete 7 work so still remaining work is 5.
So C can alone complete work 48/5. So answer is C. You can easily calculate.
Emma said:
1 decade ago
Where does 48 come from in this come equation?
Abi said:
1 decade ago
A can do work in 16 days.
Then, A's 1 day work = 1/16.
Meanwhile, C's 1 day work = 5/48 (our ans).
Then, C can do work in 48/5 days.
Then, A's 1 day work = 1/16.
Meanwhile, C's 1 day work = 5/48 (our ans).
Then, C can do work in 48/5 days.
Ankit said:
1 decade ago
How to change this 5/48 to 48/5?
Soumya said:
1 decade ago
@Deepika.
C's 1 day work is 5/48.
Here we require C's total work.
Total work should be taken as '1'.
So, 1 day work i.e,5/48*number of days used to complete the work(unknown, so take it as 'x') = total work 1.
Simply, 5/48*x = 1.
5x = 48.
x = 48/5.
So C's total work is 48/5.
C's 1 day work is 5/48.
Here we require C's total work.
Total work should be taken as '1'.
So, 1 day work i.e,5/48*number of days used to complete the work(unknown, so take it as 'x') = total work 1.
Simply, 5/48*x = 1.
5x = 48.
x = 48/5.
So C's total work is 48/5.
Deepika said:
1 decade ago
How is last step is taken 5/48 is reversed to 48/5?
(1)
Suresh said:
1 decade ago
LCM of 4 & 48 is 48.
So 1/4-7/48 = (12*1-7*1)/48.
= 5/48.
So 1/4-7/48 = (12*1-7*1)/48.
= 5/48.
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