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 4 of 12.
Aditya Ranjan said:
7 years ago
@All.
In this question you've shown B is 30% slower than A but the question is A is 30% faster so if B can finish the work in 100x days or let 100 days then A would do it in 70 days only. If there is not any mistake please make sure me where am I wrong.
In this question you've shown B is 30% slower than A but the question is A is 30% faster so if B can finish the work in 100x days or let 100 days then A would do it in 70 days only. If there is not any mistake please make sure me where am I wrong.
Amisha said:
1 decade ago
A requried to work is 23 days
A is 30% more efficient than B,that means B requried 30% more time than A
so,30% of A time= 23*30/100=6.9
so time requried for B=23+30% of A= 23+6.9=29.9
now,work per day for (A+B)=1/23+1/29.9 above work as per rule
A is 30% more efficient than B,that means B requried 30% more time than A
so,30% of A time= 23*30/100=6.9
so time requried for B=23+30% of A= 23+6.9=29.9
now,work per day for (A+B)=1/23+1/29.9 above work as per rule
Janu said:
2 years ago
A is 30% efficient than B,
Then,
A = 30% + B.
A's 1 day work = 1/23.
Let, take B work as x, then B's 1 day work is 1/x.
A = 30% + B.
1/23 = 30% + 1/x.
1/23 = ( 30/100 * 1/x) + 1/x,
1/23 = 13/10x,
x = 299/10,
1/A + B = 1/23 + 10/299,
A + B = 13.
Then,
A = 30% + B.
A's 1 day work = 1/23.
Let, take B work as x, then B's 1 day work is 1/x.
A = 30% + B.
1/23 = 30% + 1/x.
1/23 = ( 30/100 * 1/x) + 1/x,
1/23 = 13/10x,
x = 299/10,
1/A + B = 1/23 + 10/299,
A + B = 13.
(16)
Deepanshu yadav said:
7 years ago
A's 1 day work=1/23.
B's 1 day work=1/23(70/100)=7/230, since B is 30 % less efficient than A.
( A+B )'s 1day work = 1/23 +7/230 = 17/230.
So both can do the work in 230/17 days = 13.529 days.
Is it correct or not?
Can anyone tell me? Please.
B's 1 day work=1/23(70/100)=7/230, since B is 30 % less efficient than A.
( A+B )'s 1day work = 1/23 +7/230 = 17/230.
So both can do the work in 230/17 days = 13.529 days.
Is it correct or not?
Can anyone tell me? Please.
Srujan said:
1 decade ago
Here we assume A=130, and B=100.
We have noticed that A's one day work ((130)%) is 1/23.
B'S one day work ((100)%) is ?
Therefore, we get B's one day work as(100*(1/23))/130) = 10/((13)*23).
A+B one day's work is 1/23 + 10/(23*13) = 1/13.
We have noticed that A's one day work ((130)%) is 1/23.
B'S one day work ((100)%) is ?
Therefore, we get B's one day work as(100*(1/23))/130) = 10/((13)*23).
A+B one day's work is 1/23 + 10/(23*13) = 1/13.
Dhvani said:
1 year ago
A = 130 %
B = 100%
Per day A's work = 1.3.
Per day B's work = 1.
Together means 1 + 1.3 = 2.3.
So,
1.3 = 1/23,
2.3 = ?.
By cross multiplication,
= (23 * 1/23)/13.
= 1/13.
= Reverse of 1/13.
= 13 days.
We get the answer as 13 days.
B = 100%
Per day A's work = 1.3.
Per day B's work = 1.
Together means 1 + 1.3 = 2.3.
So,
1.3 = 1/23,
2.3 = ?.
By cross multiplication,
= (23 * 1/23)/13.
= 1/13.
= Reverse of 1/13.
= 13 days.
We get the answer as 13 days.
(17)
Mir Rokon Uddin said:
9 years ago
It is the most easiest process.
According to working ability A = 1.3 B.
So B= A/1.3.
So, A + B = A + A/1.3
= 2.3A/1.3
= 23A/13.
A does the in 23 days.
So, (23A/13) does the work = 23 * 13/23days.
= 13days.
According to working ability A = 1.3 B.
So B= A/1.3.
So, A + B = A + A/1.3
= 2.3A/1.3
= 23A/13.
A does the in 23 days.
So, (23A/13) does the work = 23 * 13/23days.
= 13days.
Jeetu said:
1 decade ago
I agree with Shahid basha.
According to the language used in the above question base should be B's efficiency and not A's because in the given explanation to the question 100 is 76% approx of 130 and not 70% (100%-30%) as required.
According to the language used in the above question base should be B's efficiency and not A's because in the given explanation to the question 100 is 76% approx of 130 and not 70% (100%-30%) as required.
Shikha Sood said:
1 decade ago
I can explain why ratio 100:130 comes, as in problem it is given that A is 30% more effificient than B. That is A can do work in Less time so ratio By time will be A:B = 100:130 that is Time taken by A is 100 and B by 130 .......
Javid mir said:
1 decade ago
A = 23 days.
B = 30%more than A i.e, B=130% of A.
B = 130/100*23 = 299/10.
Now, A's 1 day work = 1/23.
B's 1 day work = 10/299.
Therefore, (A+B) completes 1 days work in (t)=1/23 + 10/299.
Solving for (t) we get, t=1/13.
t=13.
B = 30%more than A i.e, B=130% of A.
B = 130/100*23 = 299/10.
Now, A's 1 day work = 1/23.
B's 1 day work = 10/299.
Therefore, (A+B) completes 1 days work in (t)=1/23 + 10/299.
Solving for (t) we get, t=1/13.
t=13.
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