Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 30)
30.
A and B together can do a piece of work in 30 days. A having worked for 16 days, B finishes the remaining work alone in 44 days. In how many days shall B finish the whole work alone?
Answer: Option
Explanation:
Let A's 1 day's work = x and B's 1 day's work = y.
Then, x + y = | 1 | and 16x + 44y = 1. |
30 |
Solving these two equations, we get: x = | 1 | and y = | 1 |
60 | 60 |
![]() |
1 | . |
60 |
Hence, B alone shall finish the whole work in 60 days.
Discussion:
97 comments Page 10 of 10.
Kanna said:
1 decade ago
Let A's 1 day's work = x and B's 1 day's work = y.
Both A's and B's 1 day work=1/30
i.e (A's 1 day + B's 1 day)=1/30
i.e x + y = 1/30........eq1
now,
A having worked for 16 days, B finishes the remaining work alone in 44 days
i.e work done by A in 16 days = 16x
Remaining work done B= 1 - 16x
but Remaining work is done by B in 44days i.e 44y
i.e. 44y=1-16x
i.e 16x+44y=1........eq2
solving eq1 & eq2,
we get,x = 1/60 and y = 1/60
B's 1 day's work = 1/60.
Hence, B alone shall finish the whole work in 60 days.
Both A's and B's 1 day work=1/30
i.e (A's 1 day + B's 1 day)=1/30
i.e x + y = 1/30........eq1
now,
A having worked for 16 days, B finishes the remaining work alone in 44 days
i.e work done by A in 16 days = 16x
Remaining work done B= 1 - 16x
but Remaining work is done by B in 44days i.e 44y
i.e. 44y=1-16x
i.e 16x+44y=1........eq2
solving eq1 & eq2,
we get,x = 1/60 and y = 1/60
B's 1 day's work = 1/60.
Hence, B alone shall finish the whole work in 60 days.
(1)
Santh said:
1 decade ago
Selvi. You are wrong absolutely.
(1)
Student said:
1 decade ago
How can we write 16x+44y=1. I cant understand.
(1)
Ranjit said:
1 decade ago
How you got 16x + 44y = 1, thy said 16 days alone a worked remainig work finished by b is 44 days then how can you frame the equation from this given data, I cant get please make me to understand.
(2)
Vishal said:
1 decade ago
Above solution is not properly explained.
Let me try to make it more clear (mathematically or logically).
1 day = 24 Hours.
A worked x hours in 1 day (24 hours).
B worked y hours in 1 day (24 hours).
So, x + y = 24 hours ----- Eq 1.
Now A's 16 days' work in hours = 16 * x = 16x.
And B's 44 days' work in hours = 44 * y = 44y.
16x + 44y = 30 days together worked of A + B in hours = 30 * 24 = 720 hours.
So 16x + 44y = 720 ----- Eq 2.
Now Eq 2 - 16 * Eq 1.
16x + 44y = 720.
16x + 16y = 384.
0 + 28y = 336.
Y = 336 / 28 = 12 hours in 1 day.
So x = 12 hours in 1 day.
If A doesn't work then to B has to work 24 hours in order to finish 1 day work which is equal to 2 days for B.
So for 30 days work, B has to work 60 days (answer = 60 days).
Let me try to make it more clear (mathematically or logically).
1 day = 24 Hours.
A worked x hours in 1 day (24 hours).
B worked y hours in 1 day (24 hours).
So, x + y = 24 hours ----- Eq 1.
Now A's 16 days' work in hours = 16 * x = 16x.
And B's 44 days' work in hours = 44 * y = 44y.
16x + 44y = 30 days together worked of A + B in hours = 30 * 24 = 720 hours.
So 16x + 44y = 720 ----- Eq 2.
Now Eq 2 - 16 * Eq 1.
16x + 44y = 720.
16x + 16y = 384.
0 + 28y = 336.
Y = 336 / 28 = 12 hours in 1 day.
So x = 12 hours in 1 day.
If A doesn't work then to B has to work 24 hours in order to finish 1 day work which is equal to 2 days for B.
So for 30 days work, B has to work 60 days (answer = 60 days).
Guest said:
1 decade ago
Selvi: its wrong... because, we dont know a & b's one day work.
Selvi said:
1 decade ago
A having worked for 16 days
B finishes the remaining work alone in 44 days
so,
B finish the whole work alone is = A having worked+B finishes the remaining work alone
B alone = 16 days + 44 days
= 60 days
B finishes the remaining work alone in 44 days
so,
B finish the whole work alone is = A having worked+B finishes the remaining work alone
B alone = 16 days + 44 days
= 60 days
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