Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 4)
4.
A is thrice as good as workman as B and therefore is able to finish a job in 60 days less than B. Working together, they can do it in:
Answer: Option
Explanation:
Ratio of times taken by A and B = 1 : 3.
The time difference is (3 - 1) 2 days while B take 3 days and A takes 1 day.
If difference of time is 2 days, B takes 3 days.
| If difference of time is 60 days, B takes |  |
3 | x 60 |  |
= 90 days. |
| 2 |
So, A takes 30 days to do the work.
| A's 1 day's work = | 1 |
| 30 |
| B's 1 day's work = | 1 |
| 90 |
| (A + B)'s 1 day's work = | |
1 | + | 1 | |
= | 4 | = | 2 |
| 30 | 90 | 90 | 45 |
 A and B together can do the work in |
45 | = 22 | 1 | days. |
| 2 | 2 |
Discussion:
281 comments Page 6 of 29.
Vinod Anand said:
1 decade ago
If A is thrice as good as workman B,
Than A=3B ----(1) or B=A/3 --------(2).
If A is finish a job in 60 days less than B.
Than A = B-60.
Put the value of B from Eq.(2).
A = A/3 -60
3A = A-180
2A = 180
than A = 90 Days.
Same Put the value of A in Eq.(2).
B=90/3 = 30 Days.
So Working together (A+B) = 1/90 + 1/30.
A+B = 2/45.
or A+B =45/2 = 22.5 or 22 1/2.
Answer.22 1/2 Days.
Than A=3B ----(1) or B=A/3 --------(2).
If A is finish a job in 60 days less than B.
Than A = B-60.
Put the value of B from Eq.(2).
A = A/3 -60
3A = A-180
2A = 180
than A = 90 Days.
Same Put the value of A in Eq.(2).
B=90/3 = 30 Days.
So Working together (A+B) = 1/90 + 1/30.
A+B = 2/45.
or A+B =45/2 = 22.5 or 22 1/2.
Answer.22 1/2 Days.
JAY said:
8 years ago
LET:
A = 3B.
where:
A = 1/x and B = 1/(x+60)
so;
(1/x) = 3[ 1/(x+60) ]
X = 30.
1/A + 1/B = 1/T
1/30 + 1/(30+60) = 1/T
Then, T = 22.5 answer.
A = 3B.
where:
A = 1/x and B = 1/(x+60)
so;
(1/x) = 3[ 1/(x+60) ]
X = 30.
1/A + 1/B = 1/T
1/30 + 1/(30+60) = 1/T
Then, T = 22.5 answer.
Sindhu said:
1 decade ago
HI,
This method I feel to be quiet easier.
A is thrice as good as workman as B.
therfore,
A=3B -(1)
finish a job in 60 days less than B
1/B=60+1/A -(2)
i.e B`s One day work = A`s one day work + 60 days.
Solve (1) & (2)
we will get
A= 90;
From (1)
B=A/3
=> B= 30.
(A+B)`s 1 day work = 1/90+1/30
=2/45
=22 1/2 days
This method I feel to be quiet easier.
A is thrice as good as workman as B.
therfore,
A=3B -(1)
finish a job in 60 days less than B
1/B=60+1/A -(2)
i.e B`s One day work = A`s one day work + 60 days.
Solve (1) & (2)
we will get
A= 90;
From (1)
B=A/3
=> B= 30.
(A+B)`s 1 day work = 1/90+1/30
=2/45
=22 1/2 days
Yaswanth said:
6 years ago
Let's assume A completes its work in x days.
B completes in 3x days . since A is times efficient than B.
now, their difference is 60 days.
then, x-3x=60,
2x=60,
x=30,
A=30,B=90.
So, one days work of A and B together is A+B=1/30+1/90.
=4/90,
=2/45,
So one day work of A and B together is 2/45.
So A and B can complete the work in 45/2 days.
this equals to 22(1/2).
B completes in 3x days . since A is times efficient than B.
now, their difference is 60 days.
then, x-3x=60,
2x=60,
x=30,
A=30,B=90.
So, one days work of A and B together is A+B=1/30+1/90.
=4/90,
=2/45,
So one day work of A and B together is 2/45.
So A and B can complete the work in 45/2 days.
this equals to 22(1/2).
Jaswinder Singh said:
1 decade ago
Ratio of times taken by A and B = 1 : 3. or 1x:3x
so, we say
3x-1x=60,
2x=60,
x=30, so A will 30 day to complected a work,
B will be complete the work ie 3x, 3(30)=90days,
(A+B) 1 Day work = (1/30 + 1/90)
by solving we get,
A+B 1 Day work = 2/45,
so A and B together can complete work in 45/2 Days.
so, we say
3x-1x=60,
2x=60,
x=30, so A will 30 day to complected a work,
B will be complete the work ie 3x, 3(30)=90days,
(A+B) 1 Day work = (1/30 + 1/90)
by solving we get,
A+B 1 Day work = 2/45,
so A and B together can complete work in 45/2 Days.
Sanishk said:
6 years ago
What is wrong with the below step?
A's 1-day work = 1/y.
Then, B's 1-day work = 1/3y.
Now,
A completes work before 60 days compared to B.
So,
1/y - 1/3y = 1/60
2/3y = 1/60
y = 40.
i.e., A completes in 40 days and B completes in 120 days,
Now, working together they complete in
1/A + 1/B = 1/40+ 1/120 = 1/30.
So, Together they complete in 30 days.
A's 1-day work = 1/y.
Then, B's 1-day work = 1/3y.
Now,
A completes work before 60 days compared to B.
So,
1/y - 1/3y = 1/60
2/3y = 1/60
y = 40.
i.e., A completes in 40 days and B completes in 120 days,
Now, working together they complete in
1/A + 1/B = 1/40+ 1/120 = 1/30.
So, Together they complete in 30 days.
Jeeva said:
4 years ago
a ------ b
x ------ 3x.
1/3 of the work is remaining = 1 - 1/3.
= 2/3.
2/3 of the work is completed by b = 60 days.
one of the work is completed by b = 60 * 3/2.
b = 90.
B one day work = 1/90.
A one-day work = 1/30.
a+b = 1/30 + 1/90.
a+b = 4/90
a+b = 2/45.
A and B together can do the work = 45/2.
x ------ 3x.
1/3 of the work is remaining = 1 - 1/3.
= 2/3.
2/3 of the work is completed by b = 60 days.
one of the work is completed by b = 60 * 3/2.
b = 90.
B one day work = 1/90.
A one-day work = 1/30.
a+b = 1/30 + 1/90.
a+b = 4/90
a+b = 2/45.
A and B together can do the work = 45/2.
(1)
Purusottam said:
8 years ago
The answer must be 45 days.
Let B does the work in x days.
Now let's think about A's efficiency.
As far as the question is concerned,
3*100/x =100/60.
So, x=180,
Efficiency of A+B=100/60+100/180,
= 20/9%.
So 20/9...........1
1..............9/20
100..........9/20*100 .
=45.
Let B does the work in x days.
Now let's think about A's efficiency.
As far as the question is concerned,
3*100/x =100/60.
So, x=180,
Efficiency of A+B=100/60+100/180,
= 20/9%.
So 20/9...........1
1..............9/20
100..........9/20*100 .
=45.
Nurun Nobi Khokon said:
7 years ago
Let A take x days
So, B takes x+60 days
3x = x+60 (B took 3 times more, so to make the equation equal he have to multiply the days taken by A by 3).
or, 2x = 60,
or, x = 30 days.
A takes 30 days and b takes 30+60 or 90 days.,
Now, (A+B)'s 1 day's work = (1/30+1/90) or 4/90 or 2/45,
So, total days required to do the whole work, 45/2 or 22.5 days.
So, B takes x+60 days
3x = x+60 (B took 3 times more, so to make the equation equal he have to multiply the days taken by A by 3).
or, 2x = 60,
or, x = 30 days.
A takes 30 days and b takes 30+60 or 90 days.,
Now, (A+B)'s 1 day's work = (1/30+1/90) or 4/90 or 2/45,
So, total days required to do the whole work, 45/2 or 22.5 days.
Sharad said:
1 decade ago
Given A is thrice as good as B,
Therefore 3:1.
i.e 3x:x (ability to work). (Time taken is inverse of work).
Time taken by A and B to complete work = x:3x.
Difference A-B = 60.
Therefore x-3x = 60.
x = 60/2 = 30.
Now x:3x = 30:3(30).
= 30:90.
(A+B) 's 1 day = (1/30)+(1/90).
1 day = 2/45 work.
45/2 day = 1 work.
22. 5 day = 1 work.
Therefore 3:1.
i.e 3x:x (ability to work). (Time taken is inverse of work).
Time taken by A and B to complete work = x:3x.
Difference A-B = 60.
Therefore x-3x = 60.
x = 60/2 = 30.
Now x:3x = 30:3(30).
= 30:90.
(A+B) 's 1 day = (1/30)+(1/90).
1 day = 2/45 work.
45/2 day = 1 work.
22. 5 day = 1 work.
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