Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 9)
9.
A does 80% of a work in 20 days. He then calls in B and they together finish the remaining work in 3 days. How long B alone would take to do the whole work?
Answer: Option
Explanation:
Whole work is done by A in | ![]() |
20 x | 5 | ![]() |
= 25 days. |
4 |
Now, | ![]() |
1 - | 4 | ![]() |
i.e., | 1 | work is done by A and B in 3 days. |
5 | 5 |
Whole work will be done by A and B in (3 x 5) = 15 days.
A's 1 day's work = | 1 | , (A + B)'s 1 day's work = | 1 | . |
25 | 15 |
![]() |
![]() |
1 | - | 1 | ![]() |
= | 4 | = | 2 | . |
15 | 25 | 150 | 75 |
So, B alone would do the work in | 75 | = 37 | 1 | days. |
2 | 2 |
Discussion:
164 comments Page 7 of 17.
Sivapriya said:
10 years ago
Hai guys I have one doubt. Will you please explain me. Geore do 3/5th work in 9 days. He then call paul and finish in 4 days. How long paul take to work by himself?
SUJALA said:
10 years ago
A is doing 80% work in 20 days.
80/100 = 20.
4/5 = 20/1 (cross multiplication).
= 25 days.
It means a can take time to complete 100% of work for 25 days.
A+B is doing 20% of work in 3 days.
= 20/100 = 3/1 (cross multiplication) = 15 days.
Now B to get complete 100% of work is?
(A+B)-A = B.
= 1/15-1/25 = 2/75 = 37*1/2.
80/100 = 20.
4/5 = 20/1 (cross multiplication).
= 25 days.
It means a can take time to complete 100% of work for 25 days.
A+B is doing 20% of work in 3 days.
= 20/100 = 3/1 (cross multiplication) = 15 days.
Now B to get complete 100% of work is?
(A+B)-A = B.
= 1/15-1/25 = 2/75 = 37*1/2.
Punitsw said:
10 years ago
In simple words:
A completes 80% in 20 days so would 92% in 23 days.
Remaining 8% completed by B in 3 days (21 - 23rd).
Now if B completes 8% in 3 days. So will be able to complete 100% in 37.5 days (3 x 100/8).
A completes 80% in 20 days so would 92% in 23 days.
Remaining 8% completed by B in 3 days (21 - 23rd).
Now if B completes 8% in 3 days. So will be able to complete 100% in 37.5 days (3 x 100/8).
Inna said:
10 years ago
A's work 80% --- 20.
100% --- 25 (A).
A + B work (the remaining work means) 20% --- 3.
100% --- 15 (A+B).
(A+B) - A = B.
= 25*15/10 = 75/2 = 37*1/2.
100% --- 25 (A).
A + B work (the remaining work means) 20% --- 3.
100% --- 15 (A+B).
(A+B) - A = B.
= 25*15/10 = 75/2 = 37*1/2.
Saravanan said:
10 years ago
Now I understand this concept.
Parvin Kumar said:
9 years ago
Hi all,
Work Completed = 80% = 80/100 = 4/5.
So, Remaining = 1- 4/5 = 1/5.
A + B complete this in 3 days so if they had continued total time required will be 5 * 3 = 15 days.
A individual complete it in 5/4 * 20 = 25 Days.
Then, B individual 1 day Work = 1/(A + B) - 1/A = 1/15 - 1/25 = 2/75.
So, B will complete whole work in 75/2 = 37 1/2.
Work Completed = 80% = 80/100 = 4/5.
So, Remaining = 1- 4/5 = 1/5.
A + B complete this in 3 days so if they had continued total time required will be 5 * 3 = 15 days.
A individual complete it in 5/4 * 20 = 25 Days.
Then, B individual 1 day Work = 1/(A + B) - 1/A = 1/15 - 1/25 = 2/75.
So, B will complete whole work in 75/2 = 37 1/2.
Rahul said:
9 years ago
Hi, one easy and time-saving method is:
A done 80% work in 20 days.
So, one day work of A is = 80/20 = 4%.
Here, remaining work is = 100 - 80.
=20%.
A and B both together remaining work and they take 3 days to accomplish it.
During this three day, A's work is = 4% * 3 = 12%.
Then, B's work during 3 days = 8%.
Work - Days.
8% - 3.
100% - (?).
100 * 3/8 = 300/8 = 37.5 days.
A done 80% work in 20 days.
So, one day work of A is = 80/20 = 4%.
Here, remaining work is = 100 - 80.
=20%.
A and B both together remaining work and they take 3 days to accomplish it.
During this three day, A's work is = 4% * 3 = 12%.
Then, B's work during 3 days = 8%.
Work - Days.
8% - 3.
100% - (?).
100 * 3/8 = 300/8 = 37.5 days.
Likhitha said:
9 years ago
A does 80% of work in 20 days.
Then A can do 100% of work in 25 days and 20% of work in 5 days.
A + B together finish the remaining 20% of work in 3 days.
For 20% of work B alone:
3/5 + 3/x = 1.
x = 7.5 days.
For 20% of work B alone takes 7.5 days then for 100% of work B takes,
20% = 7.5.
100% = ?.
100 * 7.5/20 = 37.5 = 37 1/2.
Then A can do 100% of work in 25 days and 20% of work in 5 days.
A + B together finish the remaining 20% of work in 3 days.
For 20% of work B alone:
3/5 + 3/x = 1.
x = 7.5 days.
For 20% of work B alone takes 7.5 days then for 100% of work B takes,
20% = 7.5.
100% = ?.
100 * 7.5/20 = 37.5 = 37 1/2.
Rajkanya Saha said:
9 years ago
Too good @Baskar.
Thanks for explaining the answer.
Thanks for explaining the answer.
Aakash Reddy said:
9 years ago
==>> A can do 80% W ---------> 20 days.
=> Then, 100% W ---------->
=> How many days(D), By Cross-multiplying we get,
D = (100*20)/80 ==> D = 25.
i.e., A can do 100% of the work in 25 days.
So, A's 1 day work, i.e., 1/A = 1/25 -----------------------(1)
The remaining work is 20%.
==>> Given A+B can do the 20% W --------> 3 days.
=> Then, 100% W ------------------------>
=> How many days(D), By cross-multiplying we get,
D = (100*3)/20 ==> D=15.
i.e., A+B can do 100% of work in 15 days.
So, A & B one day work i.e., 1/A + 1/B = 1/15 -----(2)
Solving 1 & 2, we get B's 1-day work as 1/B = 2/75.
So,
B alone would take to do the whole work i.e., B = 75/2 = 37(1/2) days.
=> Then, 100% W ---------->
=> How many days(D), By Cross-multiplying we get,
D = (100*20)/80 ==> D = 25.
i.e., A can do 100% of the work in 25 days.
So, A's 1 day work, i.e., 1/A = 1/25 -----------------------(1)
The remaining work is 20%.
==>> Given A+B can do the 20% W --------> 3 days.
=> Then, 100% W ------------------------>
=> How many days(D), By cross-multiplying we get,
D = (100*3)/20 ==> D=15.
i.e., A+B can do 100% of work in 15 days.
So, A & B one day work i.e., 1/A + 1/B = 1/15 -----(2)
Solving 1 & 2, we get B's 1-day work as 1/B = 2/75.
So,
B alone would take to do the whole work i.e., B = 75/2 = 37(1/2) days.
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