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 5 of 12.
Ajay said:
6 years ago
First, solve percentage i.e-30% = 3/10.
From that fraction, we can calculate the efficiency of both A and B which is 13 and 10.
Work=time x efficiency.
Total work =23x13
Time is taken by both to do the work=23x13/23,
=13 days.
From that fraction, we can calculate the efficiency of both A and B which is 13 and 10.
Work=time x efficiency.
Total work =23x13
Time is taken by both to do the work=23x13/23,
=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.
Riad said:
8 years ago
In 1 day, B can do x portion of the work.
So, A can do 1.3x portion of the work.
So, 1.3x=1/23..x=1/(23*1.3) portion of the work.. together in 1 day can do. (1/23+1/29.9)...Then in 13 day they can complete the whole work.
So, A can do 1.3x portion of the work.
So, 1.3x=1/23..x=1/(23*1.3) portion of the work.. together in 1 day can do. (1/23+1/29.9)...Then in 13 day they can complete the whole work.
Manasa said:
1 decade ago
@nayana
A can complete the work in 23 days.
A's 1 day work is 1/23
in similar manner
B can complete the work in 299/10 days
then B's 1 day work is 10/299
now they considered (A+B) 1 days work
therefore,(1/23)+(10/229)=1/13
A can complete the work in 23 days.
A's 1 day work is 1/23
in similar manner
B can complete the work in 299/10 days
then B's 1 day work is 10/299
now they considered (A+B) 1 days work
therefore,(1/23)+(10/229)=1/13
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 :).
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.
Deepak said:
1 decade ago
WORKING DAYS FOR A = 23 DAYS,
IN ONE DAY A = 1/23,
Since A 30% efficient ,WORKING DAYS FOR B=23+23*30/100=299/10 DAYS.
IN ONE DAY B = 1/(299/10)=10/299.
(A+B)*DAY = 1.
(1/23+10/299)*DAY = 1.
DAY = 299/23 = 13 DAYS.
IN ONE DAY A = 1/23,
Since A 30% efficient ,WORKING DAYS FOR B=23+23*30/100=299/10 DAYS.
IN ONE DAY B = 1/(299/10)=10/299.
(A+B)*DAY = 1.
(1/23+10/299)*DAY = 1.
DAY = 299/23 = 13 DAYS.
Tanuj Upadhyay said:
5 years ago
As given, A=B+(30% of B) i.e. A=(13B/10).
And, A=1/23 so put this value in the above equation.
We get, B=(10/23*13).
Now find, A+B => 1/23+10/23*13.
=> 1/23(1+10/13).
After solving it the value of A+B is (1/13).
And, A=1/23 so put this value in the above equation.
We get, B=(10/23*13).
Now find, A+B => 1/23+10/23*13.
=> 1/23(1+10/13).
After solving it the value of A+B is (1/13).
(3)
AJAY D said:
1 week ago
A - 130.
B - 100.
130 23.
100 B.
130 * 23 = 100 * B,
130 * 23/100 = B.
A + B = 1/23 + 100/130 * 23.
= 130/130 * 23 + 100/130*23,
= 130 + 100/130 * 23,
= 230/130 * 23,
A + B = 1/13.
B - 100.
130 23.
100 B.
130 * 23 = 100 * B,
130 * 23/100 = B.
A + B = 1/23 + 100/130 * 23.
= 130/130 * 23 + 100/130*23,
= 130 + 100/130 * 23,
= 230/130 * 23,
A + B = 1/13.
Ayush said:
5 years ago
If efficiency = a : b = 13:10.
Then time = 10:13.
10 tends to 23.,
1 ratio equal to 23/10.
A and B working together = 23*23/10.
And I got 529/10.
Whether this method is right or wrong? Please, anyone, tell me.
Then time = 10:13.
10 tends to 23.,
1 ratio equal to 23/10.
A and B working together = 23*23/10.
And I got 529/10.
Whether this method is right or wrong? Please, anyone, tell me.
(2)
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