Aptitude - Time and Work - Discussion

Guys, this is pretty simple.

Given A : B = 3 : 1, difference in time taken is 2.

Let us consider it as 2 parts.

Then it's also given that A can complete the work with 60 days gap to B. Hence we can equate these 2 parts to 60 days.

Therefore 2 parts = 60 days.

A's part is 1 parts = 30 days.

B's part is 3 parts = 90 days.

Rest you know.

Hope you intelligent guys understand :).

How to do LCM?

3x:1x

=> 3x - 1x = 60.
=> 2x = 60.
=> x = 30.
=> 3x = 90.

A+b together work = 90 * 30 / 90 + 3.

=> 2700 / 120 = 22.5 days.

Thanks for giving a different solution.

A is thrice as good as B
i.e A:B = 3:1.

The ratio will be same.
Now let a number of days for B be x.
Thus, for A it becomes (x - 60)
Now equate 3/1 = x/(x-60)(ratio of days of B to the days of A).
3x - 180 = x.
x = 180/3.
x = 90.
No of days by B is 90.
Hence days of A will be 30.

Thank you @Siva.

It's simple to learn.

Workman.

A : B.
3 : 1.

Time taken;

A : B.
1 : 3.

A) if B finish work in 30 days then, A can finish it in 10 days. Now the difference in a day is 20.

B) if B finish work in 60 days then, A can finish it in 20 days. Now the difference in a day is 40.

C) if B finish work in 90 days then, A can finish it in 30 days. Now the difference in a day is 60.

Given question. The difference is 60 days. Hence, condition c) satisfies.

A 1-day work is 1/30.

B 1-day work is 1/90.

A + B 1 day work is 1/30 + 1/90 = 4/90.

Days to complete the work is 90/4 => 22 1/2.

Let consider B can do work in n days.

1 days work of B = 1/n.
So, A = n - 60.

1 day work of A =1/ (n - 60).
As given A = 3b.
1/ (n - 60) = 3 * (1/n).
n = 90.
B can do work in 90 days.
So A can do in 30 days.
Both = (1/30) + (1/90).
= 22 (1/2).

Let A be X where as b = 3x.
So,
3x - x = 60.
x = 30.
a = 30, b = 90.

Together they can do the work in 22 (1/2) days.

Please say me any shortcut methods to solve this problem.