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:
293 comments Page 30 of 30.
Hemanthkumar said:
2 months ago
Efficiency of A: B = 3:1.
TIMES RATIO = 1 : 3.
2 PARTS - 60.
And 1 PART - 30.
So, Total work done by both = A's effi * time/both efficiency.
30 * 3/4 = 22.5.
TIMES RATIO = 1 : 3.
2 PARTS - 60.
And 1 PART - 30.
So, Total work done by both = A's effi * time/both efficiency.
30 * 3/4 = 22.5.
Arvind said:
2 months ago
A = 3.
B = 1.
Difference 2 = 60days.
Then 3 = 90 days.
1 = 30 days.
LCM = 90.
Efficiency 3+1 = 4, then 90/4 = 22.5.
B = 1.
Difference 2 = 60days.
Then 3 = 90 days.
1 = 30 days.
LCM = 90.
Efficiency 3+1 = 4, then 90/4 = 22.5.
(7)
Muni Kumar said:
7 days ago
The ratio of time taken by A and B is 1:3.
Now, if B do the work in x days, then A can do it in x-60 days.
So for A its ---> 1/x-60.
And for B its ---> 3/x.
So, 1/ x-60 = 3/x.
x = 3x - 180.
x = 90.
Now A can do it in 90-60 = 30 days.
B can do it in 90 days.
If they work together 1/30 + 1/90 = 45/2 => 22 1/2.
Now, if B do the work in x days, then A can do it in x-60 days.
So for A its ---> 1/x-60.
And for B its ---> 3/x.
So, 1/ x-60 = 3/x.
x = 3x - 180.
x = 90.
Now A can do it in 90-60 = 30 days.
B can do it in 90 days.
If they work together 1/30 + 1/90 = 45/2 => 22 1/2.
(1)
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