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 4 of 23.
Aparna said:
1 decade ago
@amit
First solve the bracket,
it is
(1/16+1/12)
First method:
Simply you can do cross multiplication
we get
(12+16)/12*16
after solving we get
7/48
Second method:
Find the lcm of denominators
that's of 12 and 16
It is 48,and multiply it with each fractions
i:e
we get
(3+4)/48
First solve the bracket,
it is
(1/16+1/12)
First method:
Simply you can do cross multiplication
we get
(12+16)/12*16
after solving we get
7/48
Second method:
Find the lcm of denominators
that's of 12 and 16
It is 48,and multiply it with each fractions
i:e
we get
(3+4)/48
Bharathi said:
1 decade ago
How should know A, B, C work is 1/4.
Geetha said:
1 decade ago
@Bharathi
In ques they have mentioned that
with the help of C they did the job in 4 days
thatsy A+B+C=1/4
In ques they have mentioned that
with the help of C they did the job in 4 days
thatsy A+B+C=1/4
Sowjanya said:
1 decade ago
Thanks geeta you solved my doubt.
Reema said:
1 decade ago
How did 5/48 come explain it?
Naresh kumar said:
1 decade ago
Thanks Aparna and Geetha. You have solved my doubt also.
I am very poor in solving such types of question.
I am very poor in solving such types of question.
Shantanu said:
1 decade ago
Reema
look
A's 1 day's work = 1/16
because he took 16 days to complete the task
similarly
C's 1 day's work =5/48
so total no. of days will be 48/5
look
A's 1 day's work = 1/16
because he took 16 days to complete the task
similarly
C's 1 day's work =5/48
so total no. of days will be 48/5
Uthappa.U.K said:
1 decade ago
1/4-7/48 cannot be equal to 5/48. Can anyone explain this to me?
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.
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