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:
281 comments Page 7 of 29.

Sindhu said:   1 decade ago
HI,
This method I feel to be quiet easier.
A is thrice as good as workman as B.
therfore,
A=3B -(1)
finish a job in 60 days less than B
1/B=60+1/A -(2)
i.e B`s One day work = A`s one day work + 60 days.
Solve (1) & (2)
we will get
A= 90;
From (1)
B=A/3
=> B= 30.

(A+B)`s 1 day work = 1/90+1/30
=2/45
=22 1/2 days

Iyappan said:   1 decade ago
Naveen kumar your explanation is beautiful for me.

Sanchi said:   1 decade ago
Very simple way.
3A=1B
B takes x days.
3 (x-60) =x
3x-x=180
X dats is B=90, A=30.
Now,
1/90+1/30=22. 5.

Nitin singh parihar said:   1 decade ago
Let B do the work in 'x' days.

So, A will take (x-60) days.

Now, ratio of A:B=1:3 (given in ques).

So, 1/3=x-60/x.

=> x=90 (B's 1 day work).

So, A's work=30 days.

Working together=1/30+1/90.

=45/2 days.

Easy and simple.

Akansha said:   1 decade ago
B takes 3 times more days than A.

i.e. B=3A.

So. B-A=60.

3A-A=60 =>.

A=30.

B=90.

Now calculate 1 day work of A and B.

Sunny said:   1 decade ago
A is thrice as good as workman as B means 1:3(Ratio)
Therefore A is able to finish a job in 60 days less than B
So A= 1/60 and B=1/60 .....(Given)
According to the ratio
A=1/60 B=1/3*60 (As we are calculating by days)
So Now A = 1/60 < B = 1/90 (A finishes work less than B)
Working together, they can do it in:
1/A+B = 1/60 + 1/90 (As we are calculating by days))
1/A+B = 2/45
So
A+B = 45/2 Days
Option (B) is the correct ans

Vidya said:   1 decade ago
Can you please solve this using unitary method. Its b'coz I follow that method.

Anji said:   1 decade ago
Let the time taken by A be x days,
then time taken by B will be 3x days.
Given that,
time taken by A to finish the work = time taken by B -60
i.e, x=3x-60
=> x=30.
Therefore, time taken by A to finish the work is 30 days.
so B takes 90 days.
Now ,work done by A & B in 1 day=1/30 + 1/90
=4/90
=2/45
Time taken by A & B to complete the work=45/2 days
=22 1/2 days

SANJEEV said:   1 decade ago
#include<stdio.h>
void main()
{
float a,b;
int c,d;
printf("enter ratio of A : B\n");
scanf("%f",&a);
printf("enter no of days lesser than B by A to complete work\n");
scanf("%f",&b);
c=ab/(a-1);
d=c-b;
printf("no of days to complete work by A and B is %d",(c*d)/(c+d));
}

Prabha said:   1 decade ago
If difference of time 2 days B takes 3 days

Similarly why don't we take difference of time 60 days B takes 60*3 is 180 days. Please explain to me ?


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