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:
283 comments Page 3 of 29.

Man said:   3 years ago
Given A:B = 1:3 => B = 3A.'

Let assume A can complete work in x days which implies B = 3x
and also given B-A = 60 => 3x-x = 60 => 2x = 60 => x = (60/2) => 30

therefore A can complete the work in 30 days. and B can complete the work in 3*30 = 90 days
1 day work of A & B together = 1/30 + 1/90 = 4/90.

If they both do 4/90 work in one day so to complete the whole 1 work they will take;
(4/90) * x = 1.
x = 90/4 = 45/2 = 22 1/2.
(47)

Kamal Thakur said:   3 years ago
Let A complete work in = x days.
B will complete work in = 3x days.

(As a is 3x sufficient so b will take 3x much time)
Also, A take 60 days less,
So days were taken by B - 60 = days taken by A
So equation will be;
3x - 60 = x,
2x = 60,
x = 30.

So A completes work in 30 days and B in 30 X x = 90
A 1-day work = 1/30,
B 1 day work = 1/90,

1 day work of A & B together = 1/30 + 1/90 = 4/90.

If they both do 4/90 work in one day so to complete the whole 1 work they will take
4/90 X x = 1.
x = 90/4 = 45/2 = 22 1/2.
(42)

Jagadish Behera said:   3 years ago
"A" is 3 times more than" B" (efficiency)

Difference = 60 days

3x-x = 60

X = 30days This is" B"

A=3 * 30 = 90 days.

So Total work =180

A=2 WORK
B=6 WORK

A+B TOGETHER CAN DO IN 180/8 = 22.5 DAYS.
(14)

Gogo said:   3 years ago
A+B = (1/30 + 1/90) = 2/45.

How we are getting this?
(8)

HARINI said:   4 years ago
Given;

A = 3B;
A = B - 60.

Substitute A = 3B in 2nd equation(a=b-60).
3B = B-60
B = 30.

Therefore; A = 3B = 90.

A+B = (1/30 + 1/90) = 2/45.
So, the answer is 22(1/2).
(24)

Muhammad said:   4 years ago
Let A's total work completion time be = n.
B's total work completion time = 3n,
Difference between B and A's daily work = 60.
3n - n = 60,
2n = 60.
n = 30.

Total daily work.
=1/3n + 1/n,
=1/90 + 1/30,
=2/45,
So total time to complete for both = 45/2 = 22.5.
(12)

Jeeva said:   4 years ago
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.
(1)

Sachin said:   4 years ago
Thanks everyone.
(1)

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)

Srikanth said:   4 years ago
Thanks @Sundhar.


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