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:
283 comments Page 28 of 29.
Saurabh said:
5 years ago
time diffence = 60days.
A is 3 times better then b.
That means A will do 3 times of work in day and B will do 1 time of A's work in 1 day
difference = 2 times.
Day difference = 60
1 time difference = 60/2 = 30.
A will do the work in 30 days.
B will do a work in 3*30 = 90days.
A is 3 times better then b.
That means A will do 3 times of work in day and B will do 1 time of A's work in 1 day
difference = 2 times.
Day difference = 60
1 time difference = 60/2 = 30.
A will do the work in 30 days.
B will do a work in 3*30 = 90days.
Sagar said:
5 years ago
Thank you for very simple answer @Malleswari.
Akshay Salekar said:
5 years ago
Hi, friends.
We know that A capability to do work is 3 times of B,ok
Then the the ratio of Efficiency is A:B=3:1
And the ratio of time (days) is A:B=1:3 ...(The ratio get reverse because Efficiency and time are inversely proportional)
Now,
Time taken by A to complete work = (X) day &
Time taken by B to complete work = (X+60) day.
*We compare the ratio of time
(X/X+60)=(1/3) get X = 30 ----> (1).
From (1) we get A need 30 Days and B need 90 days
Now take lcm of (A day and B-day).
That is LCM of (30 & 90).
A & B need to complete 90 work.
So, the efficiency of A is (3 w/d) & B's efficiency (1w/d).
When they together (A+B) = work done is (4w/d).
So (90w/(4w/d)) = 22 1/2.
We know that A capability to do work is 3 times of B,ok
Then the the ratio of Efficiency is A:B=3:1
And the ratio of time (days) is A:B=1:3 ...(The ratio get reverse because Efficiency and time are inversely proportional)
Now,
Time taken by A to complete work = (X) day &
Time taken by B to complete work = (X+60) day.
*We compare the ratio of time
(X/X+60)=(1/3) get X = 30 ----> (1).
From (1) we get A need 30 Days and B need 90 days
Now take lcm of (A day and B-day).
That is LCM of (30 & 90).
A & B need to complete 90 work.
So, the efficiency of A is (3 w/d) & B's efficiency (1w/d).
When they together (A+B) = work done is (4w/d).
So (90w/(4w/d)) = 22 1/2.
Omkar Raut said:
5 years ago
A:B = 1 : 3.
Let's say A's work is x, then x : 3x.
Now, 3x - x = 60.
Given in question.
2x = 60, x = 30
Now,A = 30, B = 90.
Let's say A's work is x, then x : 3x.
Now, 3x - x = 60.
Given in question.
2x = 60, x = 30
Now,A = 30, B = 90.
Nidhu said:
5 years ago
So, let's take the ratio as 3:1.
Consider b - 60 = a.
3a - 60 = a,
A = 30,
30 = b-60,
B = 90.
A + b = 1/30 + 1/90.
= 2/45.
Which is 45/2=22.5=22 1/2.
Consider b - 60 = a.
3a - 60 = a,
A = 30,
30 = b-60,
B = 90.
A + b = 1/30 + 1/90.
= 2/45.
Which is 45/2=22.5=22 1/2.
Bhairus said:
5 years ago
A = 3B;
A time : x-60; B time =x;
In 1 day together work =1/(x-60) +1/x.
And we also know (x-60)/x = 1/3;
From this two got x = 90 and time from eq 1 is 22.5.
A time : x-60; B time =x;
In 1 day together work =1/(x-60) +1/x.
And we also know (x-60)/x = 1/3;
From this two got x = 90 and time from eq 1 is 22.5.
Dnyaneshwar said:
5 years ago
A = 3B
Suppose workdone in 1 day by 'B'= 1/n.
Suppose workdone in 1 day by 'A'= 1/(n-60).
We get eqn;
1/(n-60) = 3(1/n).
So, n =90 days (Time taken by B to complete the work).
A= 30 days.
A+B = (1/30)+(1/90) = 22.5.
Suppose workdone in 1 day by 'B'= 1/n.
Suppose workdone in 1 day by 'A'= 1/(n-60).
We get eqn;
1/(n-60) = 3(1/n).
So, n =90 days (Time taken by B to complete the work).
A= 30 days.
A+B = (1/30)+(1/90) = 22.5.
Sanky said:
5 years ago
A:B = 1:3.
B = 3A.
Difference is 60days,
therefore B - A = 60,
3A - A = 60,
2A = 60,
A = 30 & thus B = 90.
Now, 1/30 + 1/90 = 22.5.
B = 3A.
Difference is 60days,
therefore B - A = 60,
3A - A = 60,
2A = 60,
A = 30 & thus B = 90.
Now, 1/30 + 1/90 = 22.5.
Ranjana shree said:
5 years ago
We can simplify it.
Assume if B worked for 90 days and;
C worked for 30 days.
B's 1-day work = 1/90.
A's 1-day work = 1/30.
A + B = 4/90 work.
ie, 90/4 = 22.5.
Assume if B worked for 90 days and;
C worked for 30 days.
B's 1-day work = 1/90.
A's 1-day work = 1/30.
A + B = 4/90 work.
ie, 90/4 = 22.5.
Paru said:
5 years ago
@Harsha
You gave a very good explanation, thank you.
You gave a very good explanation, thank you.
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