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.
Narayan said:
10 years ago
A = 30% of B.
Now 1 work two Man.
So, A + B = 1-------(1).
=> (30/100)B+B = 1.
=> 3B/10+B = 1.
=> 3B+10B = 10.
=> 13B = 10.
B = 10/13------(2).
(1) & (2) => A = 3/13.
Hence all total = 13 days.
Now 1 work two Man.
So, A + B = 1-------(1).
=> (30/100)B+B = 1.
=> 3B/10+B = 1.
=> 3B+10B = 10.
=> 13B = 10.
B = 10/13------(2).
(1) & (2) => A = 3/13.
Hence all total = 13 days.
Naseem Ahmad Saifi said:
10 years ago
A' s 1 day work =1/23......(1).
Now A is 30% faster of B.
So A's 1 day work = 130/100*B's 1 day work.
=> A = 13/10*B......(2).
From 1st and 2nd 13/10*B = 1/23 => B's 1 day work = 10/299......(3).
(A+B)'s 1 day work = 1/23+10/299 = 23/299.
So they complete work in 299/23 i.e. 13 days.
Now A is 30% faster of B.
So A's 1 day work = 130/100*B's 1 day work.
=> A = 13/10*B......(2).
From 1st and 2nd 13/10*B = 1/23 => B's 1 day work = 10/299......(3).
(A+B)'s 1 day work = 1/23+10/299 = 23/299.
So they complete work in 299/23 i.e. 13 days.
Durga said:
10 years ago
Please explain shortcut method.
Nishant said:
1 decade ago
Ratio of times taken by A and B = 100:130 = 10:13.
A alone can do his piece of work in 23 days.
Let B takes x days to complete a given work.
A:B = 10:13.
23:B = 10:13.
B = 299:10.
A's 1 day work = 1:23.
B's 1 day work = 10:299.
(A+B) 's 1 day work = 1:23 + 10:299 = 1:13.
So, together they will complete the work in 13 days.
A alone can do his piece of work in 23 days.
Let B takes x days to complete a given work.
A:B = 10:13.
23:B = 10:13.
B = 299:10.
A's 1 day work = 1:23.
B's 1 day work = 10:299.
(A+B) 's 1 day work = 1:23 + 10:299 = 1:13.
So, together they will complete the work in 13 days.
Dibakar said:
1 decade ago
See A alone can do the work in 23 days which is 30% less than B.
So that means B does the work in 23+0.3*23=29.9.
Now A+B together will take:
1/23+1/29.9 = 529/(23*299) = 1/13.
So it will take both of them 13 days :).
So that means B does the work in 23+0.3*23=29.9.
Now A+B together will take:
1/23+1/29.9 = 529/(23*299) = 1/13.
So it will take both of them 13 days :).
Vivek said:
1 decade ago
A can do whole work in 23 days.
We have ratio 100:130 = 10(b):13(a).
A takes 23x13 to complete a work in 299 days.
Here 299 is total work which A alone can do in 23 days.
So we know total work is 299.
Both can take 10:13 = 23 days.
Total work/together work = 299/23 = 13.
We have ratio 100:130 = 10(b):13(a).
A takes 23x13 to complete a work in 299 days.
Here 299 is total work which A alone can do in 23 days.
So we know total work is 299.
Both can take 10:13 = 23 days.
Total work/together work = 299/23 = 13.
Mehedy said:
1 decade ago
A can 23 days.
B can (23+23*30/100) = 29.9.
A 1 day = 1/23.
B 1 day = 1/29.9.
So (1/23+1/29.9) = 52.9/687.7 = 1/13 = 13.
B can (23+23*30/100) = 29.9.
A 1 day = 1/23.
B 1 day = 1/29.9.
So (1/23+1/29.9) = 52.9/687.7 = 1/13 = 13.
Shakeena said:
1 decade ago
299/10 is the one day work, so reciprocal is the days taken.
Sajid said:
1 decade ago
299/10 to convert 10/299 why please explain?
Umesh said:
1 decade ago
@Rahul.
How in 5 days please explain?
How in 5 days please explain?
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