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 5 of 23.
Jagan said:
1 decade ago
@ Uthappa
1/4-7/48 = ((48*1)-(7*4))/(4*48) //cross multiplication
=(48-28)/192 = 20/192 //ok........ now its divisible by 4
=5/48 // r u got it?
1/4-7/48 = ((48*1)-(7*4))/(4*48) //cross multiplication
=(48-28)/192 = 20/192 //ok........ now its divisible by 4
=5/48 // r u got it?
Neelam said:
1 decade ago
Thanks uthaap, I was confused about the cross multiplication. Now you explained in easy manner.
Dinesk said:
1 decade ago
Nice aparna.
Sathya said:
1 decade ago
@Shantanu.
Your explain is very short and very sweet.
Your explain is very short and very sweet.
Shalu said:
1 decade ago
@Aparna
Why you substracted 1/4 -7/48 why dont you add 1/4+7/48 ?
Why you substracted 1/4 -7/48 why dont you add 1/4+7/48 ?
Sagar said:
1 decade ago
@SHALU
SUPPOSE A,B,C ARE HAVING 10 RUPIEES
WE KNOW DAT A=5 AND B=3 NW WE HAVE TO FIND C
THEN WE WILL ADD BOTH A AND B AND REMOVE FRM TOTAL HERE ALSO SAME WE HAD DONE
UNDERSTOOD
SUPPOSE A,B,C ARE HAVING 10 RUPIEES
WE KNOW DAT A=5 AND B=3 NW WE HAVE TO FIND C
THEN WE WILL ADD BOTH A AND B AND REMOVE FRM TOTAL HERE ALSO SAME WE HAD DONE
UNDERSTOOD
Nalini said:
1 decade ago
@reema
take lcm of 1/4 - 7/48
i..e
12-7/48
= 5/48:)
got it??
take lcm of 1/4 - 7/48
i..e
12-7/48
= 5/48:)
got it??
Mallik said:
1 decade ago
Reema explained clearly.
Nikita said:
1 decade ago
1/4= 1/12+1/16+1/c
1/4-7/48=1/c
c=9*3/5
1/c= c's one day work
1/4-7/48=1/c
c=9*3/5
1/c= c's one day work
Sunil said:
1 decade ago
Why 48/5 is written? please help me.
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