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 12 of 29.

Subhendu said:   6 years ago
(3-1)=2------>60
1------>30
3------->90.

1's day work for A= 1/30
1's day work for b=1/90
Both 1's day work=(1/30+1/90)
= 4/90.

Total day = 90/4.
= 22(1/2).
The answer is B.

Dnyaneshwar said:   5 years ago
A = 3B
Suppose workdone in 1 day by 'B'= 1/n.
Suppose workdone in 1 day by 'A'= 1/(n-60).
We get eqn;
1/(n-60) = 3(1/n).

So, n =90 days (Time taken by B to complete the work).
A= 30 days.
A+B = (1/30)+(1/90) = 22.5.

Manju gouda said:   1 decade ago
Let us take B's work days be 'x'.

Then A's will be x/3.

Given difference is 60.

Therefore x-x/3 = 60 on solving x = 90.

Therefore B days = 90 & A = 30.

A&B together will be (90*30)/(90+30) = 22.5 days.

Padma said:   4 years ago
Here a simple calculation is;
A takes 1 part and B takes 3 parts.
\
So A:B ratio is 1:3.
total 4p.and the difference is 2,they did work in 60 days so 60p.
4p=60.
p=15/1.
B total working days 15*3=45.
W/t is 45/2.
(4)

Vpk said:   2 years ago
A B
(x-60) x
B=3A;

x = 3(x-60);
x = 3x - 180;
2x = 180;
x = 90;
B = 90 days
A = 30 days.

Work done in 1 day A and B together => 1/30 + 1/90=2/45;
Whole work is will be done 45/2=>22 1/2;
(103)

PARASHAR said:   1 decade ago
Simple yaar.

>A is thrice as good as workman as B and therefore is able to finish a job in 60 days=IF B TAKE 90 DAYS THEN A WILL TAKE 30 (60 DAYS LESS).

>1/30 (PLUS) 1/60=4/90==>90/4==>22. 5 SIMPLE.

Rohi said:   8 years ago
Ratio of times taken by A and B = 1:3.

Means B will take 3 times which A will do in 1 time.
If difference of time is 2 days, B takes 3 days,
If the difference of time is 10 days, B takes (3/2) * 10 =15 days.

Anshul said:   10 years ago
We can solve this question easily.

A:B = 1:3.

Difference is 60.

Hence ratio becomes:

A:B = 30:90 = 1:3.

Here we can see diff is 60.

So our answer will be 90*30/90+30 = 270/12.

= 90/4 = 45/2 = 22+1/2.

Subhranil Mondal said:   5 months ago
Assume B can do it in x days.
So A can in x/3 days.
x - x/3 = 60.
then x = 90.
So B can do the work in 90 days.
A can do it in 90/3 = 30 days.
A and B together can do it in 90 * 30/90 + 30 = 22.5 (Ans).
(18)

Poor gamer said:   1 decade ago
Let A takes x days and B takes 60+x days.
Its given that A takes 1 days when B takes 3 days.

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

Cross multiply and we get x = 30 i.e A.
X+60 = 30 + 60 = 90 i.e B.

Remaining as usual.


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