Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 16)
16.
X and Y can do a piece of work in 20 days and 12 days respectively. X started the work alone and then after 4 days Y joined him till the completion of the work. How long did the work last?
Answer: Option
Explanation:
| Work done by X in 4 days = |  |
1 | x 4 |  |
= | 1 | . |
| 20 | 5 |
| Remaining work = | |
1 - | 1 | |
= | 4 | . |
| 5 | 5 |
| (X + Y)'s 1 day's work = | |
1 | + | 1 | |
= | 8 | = | 2 | . |
| 20 | 12 | 60 | 15 |
| Now, | 2 | work is done by X and Y in 1 day. |
| 15 |
| So, | 4 | work will be done by X and Y in | |
15 | x | 4 | |
= 6 days. |
| 5 | 2 | 5 |
Hence, total time taken = (6 + 4) days = 10 days.
Discussion:
68 comments Page 6 of 7.
Nikhil said:
2 decades ago
2/15 work done by x and y in one day.
Then how you are taking reciprocal 15/2*4/5.
Then how you are taking reciprocal 15/2*4/5.
Nagu said:
2 decades ago
2/15 is work is done by X and Y in 1 day.
And 4/5 is Remaining work
suppose X and Y together take A days to complete the remaining wotk then
A*2/15 = 4/5
now A = 4/5 * 15/2
so A = 6 days
i think you understood the logic behind that
And 4/5 is Remaining work
suppose X and Y together take A days to complete the remaining wotk then
A*2/15 = 4/5
now A = 4/5 * 15/2
so A = 6 days
i think you understood the logic behind that
Anusha said:
1 decade ago
a = b+b (0.3).
(1/23) = 1.3 b.
b = (10/{23*13}).
b = (10/299).
a+b = 1/13.
So 13 days.
(1/23) = 1.3 b.
b = (10/{23*13}).
b = (10/299).
a+b = 1/13.
So 13 days.
Mahesh said:
1 decade ago
1day per x work as = 1/20 && y= 1/12..
x do work 4days ..then 4*1/20=1/5 then remaining work= 1-1/5=4/5
Remaining work's done by y i.e. 1work ---> 12
4/5 ------> x
x=4/5 * 12 = 48/5 = 9.6day nearly = 10days..
It's good method to understand GUYS..!
x do work 4days ..then 4*1/20=1/5 then remaining work= 1-1/5=4/5
Remaining work's done by y i.e. 1work ---> 12
4/5 ------> x
x=4/5 * 12 = 48/5 = 9.6day nearly = 10days..
It's good method to understand GUYS..!
Shro said:
1 decade ago
6+4 =10
Is here 4 takes from the question? " X started the work alone and then after 4 days"
Is here 4 takes from the question? " X started the work alone and then after 4 days"
ANURAG said:
1 decade ago
(x and y)'s one day work= 2/15
Therefore total number of days for the total work= 15/2
And,total number of days for 4/5 of the work=( 15/2 )*(4/5)
Hence total time = 6+4 = 10 days
Therefore total number of days for the total work= 15/2
And,total number of days for 4/5 of the work=( 15/2 )*(4/5)
Hence total time = 6+4 = 10 days
Ashish said:
1 decade ago
Work done by A in 1 day=1/20.
Work done by B in 1 day=1/12.
(A+B) 'S 1 DAY WORK=1/20+1/12=8/60.
So A can work in 4 days =4*1/20=1/5.
So remaining work=1-1/5=4/5.
So 4/5 of work done by (A+B) =4/5*60/8.
=6 DAYS.
TOTAL DAY TAKEN WILL BE=6+4=10 DAYS.
Work done by B in 1 day=1/12.
(A+B) 'S 1 DAY WORK=1/20+1/12=8/60.
So A can work in 4 days =4*1/20=1/5.
So remaining work=1-1/5=4/5.
So 4/5 of work done by (A+B) =4/5*60/8.
=6 DAYS.
TOTAL DAY TAKEN WILL BE=6+4=10 DAYS.
Padma said:
1 decade ago
A+B can work
1/20+1/12=8/60.
A can work =4*1/20=1/5.
Remaining work=1-1/5=4/5.
A+B work to days 1/n formula=60/8.
60/8*4/5=6 days.
Total day taken will be=6+4=10.
1/20+1/12=8/60.
A can work =4*1/20=1/5.
Remaining work=1-1/5=4/5.
A+B work to days 1/n formula=60/8.
60/8*4/5=6 days.
Total day taken will be=6+4=10.
Zia said:
1 decade ago
Hi, I have a shortcut.
(X-a)*Y/X+Y [X=20,Y=12,a=4]
= (20-4)*12/20+12.
= 16*12/32.
= 12/2.
= 6.
So, total time taken (6+4) = 10 days.
(X-a)*Y/X+Y [X=20,Y=12,a=4]
= (20-4)*12/20+12.
= 16*12/32.
= 12/2.
= 6.
So, total time taken (6+4) = 10 days.
Amarnath said:
1 decade ago
Sorry @Zia Don't apply formulas it loses confidence for others. Whatever they know will apply if try tell in simple answer don't tell with formulas.
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