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 27 of 29.
Nagarjun said:
1 decade ago
@Vikas
Its just cross multiplication.
If the difference is 2 days then b takes 3 days
If the difference is 60 days then b takes x days
Hence, x= (60*3)/2.
I think you got it now.
Its just cross multiplication.
If the difference is 2 days then b takes 3 days
If the difference is 60 days then b takes x days
Hence, x= (60*3)/2.
I think you got it now.
Gowri said:
1 decade ago
kl/(k)^2-1
k=3
l=60
3*60/(3)^2-1
=45/2
=22.5
k=3
l=60
3*60/(3)^2-1
=45/2
=22.5
Showry said:
1 decade ago
Hi Friends,
A:B=1:3 time taken.........since A is 3 good as B
A takes 60 days less than B
B-60:B=1:3............
i.e B-60/B=1/3..... B=90 days.... A=30......
(A+B)'s one day work (1/30+1/90) = (2/45)
Total work by (A+B) is 45/2 i.e 22 1/2.............
A:B=1:3 time taken.........since A is 3 good as B
A takes 60 days less than B
B-60:B=1:3............
i.e B-60/B=1/3..... B=90 days.... A=30......
(A+B)'s one day work (1/30+1/90) = (2/45)
Total work by (A+B) is 45/2 i.e 22 1/2.............
Vikas said:
1 decade ago
I didnt understand how did we get that (3/2)*60 ?
Ashirwad dubey said:
1 decade ago
Hi friends
k*x/(k^2-1)
k=3
x=60 given in que
ok friends
k*x/(k^2-1)
k=3
x=60 given in que
ok friends
ASHIRWAD said:
1 decade ago
HI FRIENDS THIS IS THE simplest method for solving this type of que....
K*S/(A^2-1)
where S=DAYS FOR FINISHING WORK(60 GIVEN IN QUE)
K=3 GIVEN IN QUE
K*S/(A^2-1)
where S=DAYS FOR FINISHING WORK(60 GIVEN IN QUE)
K=3 GIVEN IN QUE
Shilpi said:
1 decade ago
Can you pls teach me this equation
1/30+1/90=4/90
1/30+1/90=4/90
Naveen said:
1 decade ago
Hi, in prashanth answer, he equals the ratio 1/3 to 60-x/x but it actually x-60/x.
Harsha said:
1 decade ago
A clear approach:
Given: A's time taken:B's time taken=1:3
So A's proportion of time taken=1/(1+3)=>1/4*some x
B's proportion of time taken=3/(1+3)=>3/4*some x
As it is said that difference of time is 60 days
B's time-A's time=60
=> 3x/4-x/4=60
=>x=120
So A's proportion of time taken =x/4=120/4=30 days
B's proportion of time taken =3x/4=3*120/4=90 days
A's 1 day's work = 1/30
B's 1 day's work = 1/90
(A + B)'s 1 day's work = (1/30 + 1/90)= 4/90=2/45
A and B together can do the work in 45/2 = 22 1/2 days.
Given: A's time taken:B's time taken=1:3
So A's proportion of time taken=1/(1+3)=>1/4*some x
B's proportion of time taken=3/(1+3)=>3/4*some x
As it is said that difference of time is 60 days
B's time-A's time=60
=> 3x/4-x/4=60
=>x=120
So A's proportion of time taken =x/4=120/4=30 days
B's proportion of time taken =3x/4=3*120/4=90 days
A's 1 day's work = 1/30
B's 1 day's work = 1/90
(A + B)'s 1 day's work = (1/30 + 1/90)= 4/90=2/45
A and B together can do the work in 45/2 = 22 1/2 days.
Priya said:
1 decade ago
Please tell me why we are taking 3/2 to multiply with 60. Please explin me.
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