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:
20 days
22 1 days
2
25 days
30 days
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:
292 comments Page 1 of 30.

Arvind said:   2 weeks 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.
(2)

Hemanthkumar said:   3 weeks 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.

A K Burnwal said:   1 month ago
A is thrice of B and A takes 60 days less than B.
So,
Let A take =30 days.
B takes 30 + 60= 90 days
So, B takes = 90 Days.
One day's work of A= 1/30.
One day's work of B = 1 /90.
LCM = 90.
=3/90 + 1/90 = 4/90.
90/4 = 22.5.
(9)

Anom said:   3 months ago
How 30 days taken? Please explain me.

Shweta pal said:   3 months ago
Why we have to take work of A=x it should be 3x?

Can anyone explain?
(3)

Vishakha said:   5 months ago
According to me, it is 20 days.
(3)

Yash talavatkar said:   5 months ago
A is thrice of B and A takes 60 days less than B.
So,
Assume A takes - 30 days.
B takes - 90 Days.
One day's work of A- 1/30.
One day's work of B - 1 /90.
LCM = 90.
3/90 + 1/90 = 4/90.
90/4 = 22.5.
(27)

Nikitha Mekala said:   6 months ago
A : B is x : 3x.
A takes 60days less than B
So, 3x - x = 60.
X = 30.
Now Ais 30 and Bis 90.
Then the total work is 1/30 + 1/90
= 4/90 ==> 2/45.
So the answer ==> 45/2.
=> 22 1/2.
(29)

Ajishwarya said:   10 months ago
A is thrice as good a workman as B:
So, A = 3 B.
Substitute A as 1/60.
1/60*3 = B.
1/180 = B
Working together :
A + B = 1/60 + 1/180.
= 4/180,
= 1/45 = 45 Days.
(43)

Lalith kumar said:   11 months ago
First, A is thrice as good as B means.

If a takes a day to complete work, then b takes 3 days to complete the same work.

Here, time is inversely proportional to work.

So if b takes time T to complete, then a takes T/3 to complete.
In question, they mentioned that the time diff is 60 days.
So, T - T/3 = 60.
2T/3 = 60.
T = 90.
Now, calculate the combined work and how many days it will take.
1/30 + 1/90 = 2/45 = 22.5.
(24)


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