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 4 of 29.
Astik Mandal said:
4 years ago
A - 30d.
B - 90d.
lcm - 90(total work).
Efficiency of A - 3.
Efficiency of B - 1.
Total Efficiency = 4 total.
work/totalEfficiency=90/4=22.5.
B - 90d.
lcm - 90(total work).
Efficiency of A - 3.
Efficiency of B - 1.
Total Efficiency = 4 total.
work/totalEfficiency=90/4=22.5.
(4)
HMJ said:
4 years ago
A=3B,
A can finish the job 60 days less then B,
Say, work=60.
Capacity of B = (60/x) ----> 1
Cap of A = (60/x-60) ----> 2.
As per the condition A=3B.
Compare the above equation by putting the Capacity of A = 3 times Capacity of B.
You will get x=90.
Now put this x in above equations 1 and 2.
You will get the cap of A = 2 and Cap of B = 0.66.
Working together,
Days= Work/(cap of A + cap of B).
= 60/2.66,
= 22.5.
A can finish the job 60 days less then B,
Say, work=60.
Capacity of B = (60/x) ----> 1
Cap of A = (60/x-60) ----> 2.
As per the condition A=3B.
Compare the above equation by putting the Capacity of A = 3 times Capacity of B.
You will get x=90.
Now put this x in above equations 1 and 2.
You will get the cap of A = 2 and Cap of B = 0.66.
Working together,
Days= Work/(cap of A + cap of B).
= 60/2.66,
= 22.5.
(1)
Adheer said:
4 years ago
If B completes the work in X days, then A completes the work in X-60 days.
A is thrice good as workman as B then, the ratio of the time taken to finish the same work is 1:3
Then,
(X-60) : X :: 1 : 3
Solving this, X = 90
Means B finish the work in 90 days and A finishes the work in 30 Days,
Working together, their 1-day work,
1/90 + 1/30 = 4/90 = 2/45.
Mean working together, they finish the work in 45/2 = 22(1/2) days.
A is thrice good as workman as B then, the ratio of the time taken to finish the same work is 1:3
Then,
(X-60) : X :: 1 : 3
Solving this, X = 90
Means B finish the work in 90 days and A finishes the work in 30 Days,
Working together, their 1-day work,
1/90 + 1/30 = 4/90 = 2/45.
Mean working together, they finish the work in 45/2 = 22(1/2) days.
Apsar Khan said:
4 years ago
If A completes the work in x days, B will do the same in 3x days.
3x - x = 60.
2x = 60.
Then x = 30 and 3x = 90.
(A + B) 's 1 day's work.
=1/30 + 1/90.
= 4/90.
So, A and B together will do the work in;
= 90/4.
=>22 and 1/2.
3x - x = 60.
2x = 60.
Then x = 30 and 3x = 90.
(A + B) 's 1 day's work.
=1/30 + 1/90.
= 4/90.
So, A and B together will do the work in;
= 90/4.
=>22 and 1/2.
(1)
Ahamed said:
5 years ago
Thank you all for explaining.
Paru said:
5 years ago
@Harsha
You gave a very good explanation, thank you.
You gave a very good explanation, thank you.
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.
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.
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.
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.
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