Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 17)
17.
A is 30% more efficient than B. How much time will they, working together, take to complete a job which A alone could have done in 23 days?
Answer: Option
Explanation:
Ratio of times taken by A and B = 100 : 130 = 10 : 13.
Suppose B takes x days to do the work.
Then, 10 : 13 :: 23 : x  x = |
 |
23 x 13 |  |
x = |
299 | . |
| 10 | 10 |
| A's 1 day's work = | 1 | ; |
| 23 |
| B's 1 day's work = | 10 | . |
| 299 |
| (A + B)'s 1 day's work = | |
1 | + | 10 | |
= | 23 | = | 1 | . |
| 23 | 299 | 299 | 13 |
Therefore, A and B together can complete the work in 13 days.
Discussion:
119 comments Page 7 of 12.
Sujan Roy said:
9 years ago
130% of works = 1/23,
1% of works = 1/130 * 23,
100% of work = 100 * 1/130 * 23,
= 10/299,
Then A and B together = 1/23 + 10/299,
= 13 + 10/299,
= 23/299,
= 1/13 then 13 day is the answer.
1% of works = 1/130 * 23,
100% of work = 100 * 1/130 * 23,
= 10/299,
Then A and B together = 1/23 + 10/299,
= 13 + 10/299,
= 23/299,
= 1/13 then 13 day is the answer.
Aruna said:
9 years ago
Both can be solved using the same method.
T -25% more efficient than S =>.
For simple calculation let S be 100% efficient then T is 125%, so the time of work done ratio between T and S is T : S = 100 : 125 = 4 : 5.
Given S can do a piece of work in 20 days.
5 days of S = 4 days of T.
20 days of S= (4 * 20) /5 = 16 days.
The Same method can be used to solve the other one as well.
T -25% more efficient than S =>.
For simple calculation let S be 100% efficient then T is 125%, so the time of work done ratio between T and S is T : S = 100 : 125 = 4 : 5.
Given S can do a piece of work in 20 days.
5 days of S = 4 days of T.
20 days of S= (4 * 20) /5 = 16 days.
The Same method can be used to solve the other one as well.
Garima said:
9 years ago
Please, someone explain me the difference between the below question and the question asked in the above part.
Why different method followed to solve both but they look similar?
Sakshi can do a piece of work in 20 days. Tanya is 25% more efficient than Sakshi. The number of days taken by Tanya to do the same piece of work is?
Here the Answer is 16.
Why different method followed to solve both but they look similar?
Sakshi can do a piece of work in 20 days. Tanya is 25% more efficient than Sakshi. The number of days taken by Tanya to do the same piece of work is?
Here the Answer is 16.
Gaurav said:
9 years ago
Is any shortcut there to solve the problem? Please share with me.
Ramiz Raja said:
9 years ago
Let B takes x days to complete.
Therefore acccording to question,
1/x + 0.3/x = 23.
=> x = 23 * 1.3.
Now, (A + B)'s work 1/23 + 1/(23 * 1.3) = 1/13.
Hence required days = 13 days.
Therefore acccording to question,
1/x + 0.3/x = 23.
=> x = 23 * 1.3.
Now, (A + B)'s work 1/23 + 1/(23 * 1.3) = 1/13.
Hence required days = 13 days.
Shilajit Pramanik said:
9 years ago
A is 30% more efficient than B.
So B should the Base Value.
If B does the work in 100 days A should do it in 70 days.
Ratio of times taken by A and B = 70:100 = 7:10.
Please let me know if I am right.
Shilajit Pramanik.
So B should the Base Value.
If B does the work in 100 days A should do it in 70 days.
Ratio of times taken by A and B = 70:100 = 7:10.
Please let me know if I am right.
Shilajit Pramanik.
Shada Akhtar said:
9 years ago
A = (130/100) *B (because A is 30% more efficient than B).
A =13B/10.
A =1/23 (Given).
1/23 = 13B/10.
B = 0/299.
A + B = 1/23 +10/299.
= 23/299 = 1/13.
Hence, both will take 13 days.
A =13B/10.
A =1/23 (Given).
1/23 = 13B/10.
B = 0/299.
A + B = 1/23 +10/299.
= 23/299 = 1/13.
Hence, both will take 13 days.
Amit said:
9 years ago
We have to take 130:100? Why not 100:70?
Likhitha said:
9 years ago
A is 30% more efficient than B and A completes its work in 23 days.
100 : 23.
30 : ?.
That means for 30% 6.9 days.
A alone takes 23 days.
B alone takes 23 + 6.9 days (because B works 30% less efficient than A) = 29.9 days.
A and B together work for x days I. E.
x/23 + x/29.9 = 1(for easy calculation consider 29.9~30).
Hence, x = 13 days.
100 : 23.
30 : ?.
That means for 30% 6.9 days.
A alone takes 23 days.
B alone takes 23 + 6.9 days (because B works 30% less efficient than A) = 29.9 days.
A and B together work for x days I. E.
x/23 + x/29.9 = 1(for easy calculation consider 29.9~30).
Hence, x = 13 days.
Ramesh Naidu said:
10 years ago
Why can't we take 70% of 23 days? Then we get B's working days right?
But I'm not getting the same result why? Can you explain any one?
But I'm not getting the same result why? Can you explain any one?
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