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 ![]() |
![]() |
23 x 13 | ![]() |
![]() |
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 10 of 12.
Vishnuvardhan said:
8 years ago
As per the given data;
A = 130%B.
then
A = 130/100 B.
1/23 = 130/100 B. (as we know A=1/23)
B = 10/(13*23),
B = 10/299.
A and B together work is;
1/23 + 10/299,
23/299,
= 1/13.
Hence 13 days.
A = 130%B.
then
A = 130/100 B.
1/23 = 130/100 B. (as we know A=1/23)
B = 10/(13*23),
B = 10/299.
A and B together work is;
1/23 + 10/299,
23/299,
= 1/13.
Hence 13 days.
Ganesh said:
8 years ago
A is R% more than B, then B is less than A by.
(((R/(100+R)) * 100)%
Based on this formula,
We cant use A = 100% B = 70%.
(((R/(100+R)) * 100)%
Based on this formula,
We cant use A = 100% B = 70%.
Mannu said:
8 years ago
A alone takes 23 days to finish a job.
since A is 30% more efficient,
so B takes( A+30%(A) ) days,
i.e.,B takes ( 1.3*A = 1.3*23 ) days to complete it alone [ since A=23],
(A+B)'s one day work = ( 1/23 )+( 1/(1.3*23) ),
(A+B)'s one day work= 1/13.
Hence it takes 13 days for A alone to finish the work.
since A is 30% more efficient,
so B takes( A+30%(A) ) days,
i.e.,B takes ( 1.3*A = 1.3*23 ) days to complete it alone [ since A=23],
(A+B)'s one day work = ( 1/23 )+( 1/(1.3*23) ),
(A+B)'s one day work= 1/13.
Hence it takes 13 days for A alone to finish the work.
Radhika Sarraf said:
8 years ago
A takes 23 days to finish a work.
Since A is 30% more efficient than B, so obviously B will take 30% of time more than A to complete a work.
B=(A+30% of A),
=(23+(30/100)*23),
=(23+(69/10)),
=299/10.
So B takes 299/10 days to complete the work alone.
Now, A and B together 1 days work ((1/23)+(10/299)),
=1/13.
So both complete the work in 13 days.
HOPE THIS WILL HELP U TO UNDERSTAND THE PROBLEM IN A SIMPLE WAY.
Since A is 30% more efficient than B, so obviously B will take 30% of time more than A to complete a work.
B=(A+30% of A),
=(23+(30/100)*23),
=(23+(69/10)),
=299/10.
So B takes 299/10 days to complete the work alone.
Now, A and B together 1 days work ((1/23)+(10/299)),
=1/13.
So both complete the work in 13 days.
HOPE THIS WILL HELP U TO UNDERSTAND THE PROBLEM IN A SIMPLE WAY.
Sandeep kumar said:
8 years ago
Total work= 299.
A+B= 13+10=23.
Total time= 299/23= 13.
A+B= 13+10=23.
Total time= 299/23= 13.
ALLU said:
8 years ago
Efficiency and time are inversely proportional.
1/23 +1/(23*1.3)=1/x.
x = 13.
1/23 +1/(23*1.3)=1/x.
x = 13.
MAGGI said:
8 years ago
@Pallavi.
Ans: remaining amount f work is 1- 1/6 = 5/6.
5/6 is nothing but (1/6) 5. i.e 5 parts of 1/6.
In the question1/6 work takes 2 days and next part 50% faster.
We have 5 parts of 1/6 remaining (5/6) which is done in 5 days, each part of 1/6 takes 1 day (50% fast).
Ans: remaining amount f work is 1- 1/6 = 5/6.
5/6 is nothing but (1/6) 5. i.e 5 parts of 1/6.
In the question1/6 work takes 2 days and next part 50% faster.
We have 5 parts of 1/6 remaining (5/6) which is done in 5 days, each part of 1/6 takes 1 day (50% fast).
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.
Siddharth said:
8 years ago
Answer is 10 people.
If a is 30% efficient than b. then,
Days ratio should be
a:b = 100:130, and a=1/23.
Solving this we get,
b = (13/230).
a+b = 10.
If a is 30% efficient than b. then,
Days ratio should be
a:b = 100:130, and a=1/23.
Solving this we get,
b = (13/230).
a+b = 10.
Bhishma said:
8 years ago
A is 30% effi then B.
So B=100%
A=130% take ratio=A/B=130/100=13:10
A:B
A, 13=1/23
B, 10=B cross xly
13B=10*1/23
B=10/23*13
B=10/299
A+B=1/23+10/299=1/13 days.
So B=100%
A=130% take ratio=A/B=130/100=13:10
A:B
A, 13=1/23
B, 10=B cross xly
13B=10*1/23
B=10/23*13
B=10/299
A+B=1/23+10/299=1/13 days.
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