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 12 of 12.
Thilagavathinagarajan said:
7 years ago
Why we consider 10:13::23:x? Please explain this step.
Badal said:
7 years ago
E * d = w,
So, the Total work 13 * 23,
Together efficiency = 23.
So, (13 * 23)÷23 = 13 is the answer.
So, the Total work 13 * 23,
Together efficiency = 23.
So, (13 * 23)÷23 = 13 is the answer.
BIKKU said:
7 years ago
a : B = 13 : 10,
13 * 23 = x * 23.
x = 13.
13 * 23 = x * 23.
x = 13.
AMAN said:
7 years ago
The answer is approx 13 days.
As B would do the work in 230/7 days.
B's one day work would be 7/230.
a+b = x{1/23+7/230}=1.
x = apprx 13 days.
As B would do the work in 230/7 days.
B's one day work would be 7/230.
a+b = x{1/23+7/230}=1.
x = apprx 13 days.
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.
Bhharath said:
6 years ago
Thanks @Abhishek.
DHARADI said:
6 years ago
B = (10+13/23)12.
B = (23/23)13,
B = 13.
B = (23/23)13,
B = 13.
Sushruth said:
6 years ago
A is 30% more efficient than B.
That means A=130% speed B=100% speed assume, then convert into ratio format because 13:10 it's work, now we can convert to days 10:13 (this ratio for separate man work days)
We must now ratio formula then only we understand,
This method.
A:B=A:B.
Also we write A:B::A:B.
Now apply
10:13::23:X ( Formula A:B::c:d =>A*d=B*c ).
Now we can solve that,
10X=13*23.
X=(13*23)/10.
NNow we got X value X =299/10 days for B.
B 1 day work is 299/10.
Then as usually go next steps.
That means A=130% speed B=100% speed assume, then convert into ratio format because 13:10 it's work, now we can convert to days 10:13 (this ratio for separate man work days)
We must now ratio formula then only we understand,
This method.
A:B=A:B.
Also we write A:B::A:B.
Now apply
10:13::23:X ( Formula A:B::c:d =>A*d=B*c ).
Now we can solve that,
10X=13*23.
X=(13*23)/10.
NNow we got X value X =299/10 days for B.
B 1 day work is 299/10.
Then as usually go next steps.
Chandradeepa said:
6 years ago
Why should we consider only 100 and 130?
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