Aptitude - Time and Work - Discussion

Ratio of A:B=1:3(efficiency).
=3:1(time will be opposite of efficiency).
Time difference between A:B=2.
2 denotes =60,
1 denotes=60/2=30 A,
3 denotes =60/2*3=90 B calculate L. C. M of A &B = 90,
A+B=90/4= 22(1/2)-Ans.

W1/w2 = d2/d1.
W1 = 3w2.
And d1 = d2-60.
So,
3w2/w2 = d2/d2-60,
d2 = 90,
d1 = d2 - 60 = 90 - 60 = 30.
1/90 + 1/30 = 1/22.5.
Ans 22 * 1/2.

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.

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.

Thanks everyone.

a ------ b
x ------ 3x.

1/3 of the work is remaining = 1 - 1/3.
= 2/3.

2/3 of the work is completed by b = 60 days.
one of the work is completed by b = 60 * 3/2.
b = 90.
B one day work = 1/90.
A one-day work = 1/30.
a+b = 1/30 + 1/90.
a+b = 4/90
a+b = 2/45.

A and B together can do the work = 45/2.

3/1 = (B)/(B-60).
As work done and time are inversely related,
so, B = 90, A = 30.
(1/90 + 1/30) = (2/45),
So, 22 1/5.

Please tell me how you have calculated differece of time 2 days.

Hi Guys,

Let me do the same thing with different values.

Given statement : "A is thrice as good as workman as B"
Time difference : 60 days.


If B takes 12 days to complete a work, A will take only 4 days to complete the same work.

So, B takes 12 days whereas A takes 4 days only (because A is thrice as good as B).

Here time difference is 12 - 4 = 8 days.

If the time difference is 8 days, B takes 12 days.

Similarly if the time difference is 60 days, then B takes (12/8 * 60) = 90 days.

...Rest thing you can understand from the explanation part.

Dear Friends,

In this question atlast we got (a+b)'s 1 day work=2/45.

How it is changed to be an A and B are together can do the work in 45/2.