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?
23 days
37 days
37
40 days
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 |
 B's 1 day's work = |
|
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 9 of 17.
Vishnu said:
8 years ago
Very simple,
A's 1 day work = (0.8/20).
(a+b)'s 1 day work = (0.2/3).
So, b's work = (0.2/3) - (0.8/20).
= 2/75.
Therefore days taken by B = 75/2 = 37 1/2.
A's 1 day work = (0.8/20).
(a+b)'s 1 day work = (0.2/3).
So, b's work = (0.2/3) - (0.8/20).
= 2/75.
Therefore days taken by B = 75/2 = 37 1/2.
P srinivas Rao said:
8 years ago
A 80, of work = 80/100= 4/5 = 1/5.
A 100, of whole work = 100/80*20=25.
remaining work (A+B)= 1/5= 3days.
(A+B) total work= 3*5/1= 15 days.
B whole work= 25*15/10=37.5 answer.
A 100, of whole work = 100/80*20=25.
remaining work (A+B)= 1/5= 3days.
(A+B) total work= 3*5/1= 15 days.
B whole work= 25*15/10=37.5 answer.
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?
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.
Keshav T said:
3 years ago
A = 20/(80/100)=20/(4/5)
A = 20*5/4.
A = 25 days i.e 1/25 days.
1-(4/5 )work is done = 1/5.
A+B = 1/15.
1/15 - 1/25 = 2/75.
75/2 i e 37(1/2) days.
A = 20*5/4.
A = 25 days i.e 1/25 days.
1-(4/5 )work is done = 1/5.
A+B = 1/15.
1/15 - 1/25 = 2/75.
75/2 i e 37(1/2) days.
(21)
Namrata Gujar said:
4 years ago
A=80%
Remain 100 - 80 = 20%.
A = (1/20) * (80/100) = 1/25.
A+b = (1/3)+(20/100) = 1/15.
A+b.
(1/25) + b = 1/15.
B = 2/75,
B = 75/2,
B = 37(1/2).
Remain 100 - 80 = 20%.
A = (1/20) * (80/100) = 1/25.
A+b = (1/3)+(20/100) = 1/15.
A+b.
(1/25) + b = 1/15.
B = 2/75,
B = 75/2,
B = 37(1/2).
(1)
Srini said:
1 decade ago
A's 20% work in 5 days and A+B'in 3 days,
So B's 20 work in (1/3 - 1/5) = 2/15 i.e 15/2.
So B's 100% work in (15/2)*5 = 75/2 = 37.5 days.
So B's 20 work in (1/3 - 1/5) = 2/15 i.e 15/2.
So B's 100% work in (15/2)*5 = 75/2 = 37.5 days.
VIKRAM SIHAG said:
1 decade ago
Efficeny of A+B = 20/3 = 6.66.
EFFICENCY OF A = 80/20 = 4.00.
THEN EFFICENCY OF B = 6.66-4.00 = 2.66.
DAYS TAKEN BY B = 100/2.66 = 37.5.
EFFICENCY OF A = 80/20 = 4.00.
THEN EFFICENCY OF B = 6.66-4.00 = 2.66.
DAYS TAKEN BY B = 100/2.66 = 37.5.
Gaurav gupta said:
1 decade ago
Here is the solution to get total work days of A.
80% work can done in 20 days.
So 1% can be done in (20/80%) = (20/80)*100 = 25 days.
80% work can done in 20 days.
So 1% can be done in (20/80%) = (20/80)*100 = 25 days.
Milan said:
4 years ago
Here;
20 is 80 %,
25 is 100%,
A+B = 3 days this is 20 %.
20% * 5 = 3 * 5 for 100% work,
B= A+B- A.
B=1/15- 1/25,
B = 2/ 75 = 37.5.
20 is 80 %,
25 is 100%,
A+B = 3 days this is 20 %.
20% * 5 = 3 * 5 for 100% work,
B= A+B- A.
B=1/15- 1/25,
B = 2/ 75 = 37.5.
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