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:
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 25 of 29.
Jeev said:
6 years ago
3A = B.
If 60 is less than b(then 60 is two times of a)
then A=30,
b = 3 * 30 = 90,
a+b=1/30+1/90,
3*1/90+1/90,
(3+1)/90.
Where 4/90(to get days upside down).
90/4 = 22(1/2) days.
If 60 is less than b(then 60 is two times of a)
then A=30,
b = 3 * 30 = 90,
a+b=1/30+1/90,
3*1/90+1/90,
(3+1)/90.
Where 4/90(to get days upside down).
90/4 = 22(1/2) days.
Chacha said:
6 years ago
It's simply.
3a = b.
3a = b.
Manohar said:
6 years ago
A+B = 1/60 + 1/180.
A is three times more efficient than B.
(So that if a takes 60 days then B takes 180 days).
And therefore;
2(A+B) = 180/4 = 22 * 1/2.
A is three times more efficient than B.
(So that if a takes 60 days then B takes 180 days).
And therefore;
2(A+B) = 180/4 = 22 * 1/2.
Chawdharya said:
6 years ago
A : B
TIME 1/3 : 1.
DAYS X-60 : X.
X-60/X = 1/3,
X= 90,
X-60 = 30.
A work efficiency = 1/90,
B work efficiency = 1/30,
A+B work efficiency = 1/90+1/30,
= 2/45,
work efficiency = work/time.
work is constant,so time = 45/2.
= 22.5.
TIME 1/3 : 1.
DAYS X-60 : X.
X-60/X = 1/3,
X= 90,
X-60 = 30.
A work efficiency = 1/90,
B work efficiency = 1/30,
A+B work efficiency = 1/90+1/30,
= 2/45,
work efficiency = work/time.
work is constant,so time = 45/2.
= 22.5.
Ameer said:
6 years ago
Thank you, excellent explanation.
a = 3b --> (1).
a-b = 60.
3b-b = 60.
2b = 60.
b = 30.
If b = 30 then from 1a = 3 x 30 = 90.
Now,
= 1/30+1/90.
= 3+1/90.
= 4/90 = 2/45.
= 45/2 = 22.5 days.
a = 3b --> (1).
a-b = 60.
3b-b = 60.
2b = 60.
b = 30.
If b = 30 then from 1a = 3 x 30 = 90.
Now,
= 1/30+1/90.
= 3+1/90.
= 4/90 = 2/45.
= 45/2 = 22.5 days.
SAMANTH KUMAR said:
6 years ago
Let A=X ,B=X+60 (GIVEN A TAKES 60 DAYS LESS THAN B,I CONSIDERED B TAKES 60 MORE DAYS THAN A).
Now, LCM OF X,(X+60) = X*(X+60),
Efficiency of A=(X*(X+60)) / X = X+60,
Efficiency of B=(X*(X+60)) / (X+60) = X.
Total work of A&B = (X(X+60))/(X+X+60),
We have A=3B (GIVEN).
X = 3(X+60),
X = 30.
Put in the equation and get the answer 45/2 =22(1/2).
Now, LCM OF X,(X+60) = X*(X+60),
Efficiency of A=(X*(X+60)) / X = X+60,
Efficiency of B=(X*(X+60)) / (X+60) = X.
Total work of A&B = (X(X+60))/(X+X+60),
We have A=3B (GIVEN).
X = 3(X+60),
X = 30.
Put in the equation and get the answer 45/2 =22(1/2).
Priya said:
6 years ago
The solution is;
A = x ,
B = 3x
x = 3x-60
x = 30
A = 30; B = 90;
1/30 + 1/90 = 2/45 = 22.5 days.
A = x ,
B = 3x
x = 3x-60
x = 30
A = 30; B = 90;
1/30 + 1/90 = 2/45 = 22.5 days.
Harsh said:
6 years ago
I am not understanding anything this, please explain.
Anitha said:
6 years ago
A:B = 1:3
2p = 60
P = 30
30 : 90
1/30 + 1/90 = 2/45 = 22.5.
2p = 60
P = 30
30 : 90
1/30 + 1/90 = 2/45 = 22.5.
Sai said:
6 years ago
A is thrice as B, A:B=1:3.
B takes 60 days more than A to complete the work.
Lets consider A to complete the work in x days, therefore, B completes the same work in (x+60) days, x:(x+60).
Therefore,
As these are equally related to one and other;
1:3::x:(x+60).
Cross multiply we get x=30 days ie A can finish the work in 30 days,
Therefore B can do it in 90 days ie 3 times more days given.
Therefore:
(1÷30)+(1÷90).
= 22.5 days.
B takes 60 days more than A to complete the work.
Lets consider A to complete the work in x days, therefore, B completes the same work in (x+60) days, x:(x+60).
Therefore,
As these are equally related to one and other;
1:3::x:(x+60).
Cross multiply we get x=30 days ie A can finish the work in 30 days,
Therefore B can do it in 90 days ie 3 times more days given.
Therefore:
(1÷30)+(1÷90).
= 22.5 days.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers