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:
287 comments Page 12 of 29.
Tiya said:
9 years ago
Please solve this question.
If the ratio of work efficiency of A and B is 3:2. If A and B together finish a work in 5 days in how much days B alone complete the work?
If the ratio of work efficiency of A and B is 3:2. If A and B together finish a work in 5 days in how much days B alone complete the work?
Haritha said:
9 years ago
It's a clear explanation.
Thank you @Sheetal.
Thank you @Sheetal.
Pramod patel said:
9 years ago
I think the best and universal approach is this:
A can do the work in X days, B takes X+60 days for same work,
But (X+60)/X=3/1 as time taken by A and B is in 1:3 ratio,
Solving we get X=30,
A's one day work is 1/30,
B's one day work is 1/90,
combining their one day work we get 1/30+1/90=2/45,
total time taken by them is 45/2.
A can do the work in X days, B takes X+60 days for same work,
But (X+60)/X=3/1 as time taken by A and B is in 1:3 ratio,
Solving we get X=30,
A's one day work is 1/30,
B's one day work is 1/90,
combining their one day work we get 1/30+1/90=2/45,
total time taken by them is 45/2.
Nagesh said:
9 years ago
Thank you for all the given explanation.
Sumanth said:
9 years ago
Thanks for your explanation @Indhu.
Rakesh said:
9 years ago
How 3/2? Explain.
Esrak Ahmed Kafi said:
9 years ago
Let B can do it in 3x days.
So, A can do it in X days.
According to Question,
3x-x = 60.
So, X = 30.
So, A can do it 30 days while B can do it in 90 days.
Now in (1/30+1/90) days A & B can together do the work.
=45/2 = 22.5 days.
So, A can do it in X days.
According to Question,
3x-x = 60.
So, X = 30.
So, A can do it 30 days while B can do it in 90 days.
Now in (1/30+1/90) days A & B can together do the work.
=45/2 = 22.5 days.
Sasikumar said:
9 years ago
Thanks @Deepti.
Sambhav said:
9 years ago
Hi guys.
It is given that A is thrice efficient then B then the efficiency of A is 3x and that of Y is x. then no of days are For A is(60-y) and for B is y. Then total work done is constant then
3x*(60-y) = x * y.
Then y = 45.
Then total work done by A is 45 X.
And rate of work of A and B will be 3x and x and if they work together the rate will be 4X.
So no of days will be = 45/4.
It is given that A is thrice efficient then B then the efficiency of A is 3x and that of Y is x. then no of days are For A is(60-y) and for B is y. Then total work done is constant then
3x*(60-y) = x * y.
Then y = 45.
Then total work done by A is 45 X.
And rate of work of A and B will be 3x and x and if they work together the rate will be 4X.
So no of days will be = 45/4.
Dhruv said:
9 years ago
Hi, According to me, the solution is;
A= 3B + 60,
So ,
A + B = 0
3B + 60 + B = 0
B = -15.
How to get the correct answer? Please, anyone explain me.
A= 3B + 60,
So ,
A + B = 0
3B + 60 + B = 0
B = -15.
How to get the correct answer? Please, anyone explain me.
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