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 8 of 12.
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.
Gaurav said:
9 years ago
Is any shortcut there to solve the problem? Please share with me.
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.
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.
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.
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.
Kranthi said:
9 years ago
Shortcut and Easy Method.
A work - 100 % - 23
B work - 130 %.
130/100 * 23 = 299/10,
A + B 1 day work = 1/23 + 10/299,
13 + 10/299 = 23/299 = 1/13,
13 Days.
A work - 100 % - 23
B work - 130 %.
130/100 * 23 = 299/10,
A + B 1 day work = 1/23 + 10/299,
13 + 10/299 = 23/299 = 1/13,
13 Days.
Kalai said:
9 years ago
Why can't we use ratio as A:B -> 70:100?
Krish Sapkota said:
9 years ago
I think ratio taken may be wrong (100 : 130). it should be 130 : 100.
Please confirm it guys.
Please confirm it guys.
Gaurank Verma said:
9 years ago
A can do a work in 23 days.
So,
B can do a work in [ 23 + (30/100)*23] = 29.9 days or ~30 days.
Now,
A------------> 23 days.
B------------> 30 days.
LCM(23,30)= 690 (consider it as whole work).
Hence,
A can do 30 part of a work in 1 day.
B can do 23 part of a work in 1 day.
Therefore,
Both A+B can do 53 part of work in 1 day.
Hence, to finish whole work (i.e., 690) (A + B) will take (690/53) = 13.01 days or ~13 days
So,
B can do a work in [ 23 + (30/100)*23] = 29.9 days or ~30 days.
Now,
A------------> 23 days.
B------------> 30 days.
LCM(23,30)= 690 (consider it as whole work).
Hence,
A can do 30 part of a work in 1 day.
B can do 23 part of a work in 1 day.
Therefore,
Both A+B can do 53 part of work in 1 day.
Hence, to finish whole work (i.e., 690) (A + B) will take (690/53) = 13.01 days or ~13 days
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