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 17 of 29.
Nidhu said:
5 years ago
So, let's take the ratio as 3:1.
Consider b - 60 = a.
3a - 60 = a,
A = 30,
30 = b-60,
B = 90.
A + b = 1/30 + 1/90.
= 2/45.
Which is 45/2=22.5=22 1/2.
Consider b - 60 = a.
3a - 60 = a,
A = 30,
30 = b-60,
B = 90.
A + b = 1/30 + 1/90.
= 2/45.
Which is 45/2=22.5=22 1/2.
Divyanshu Dwivedi said:
1 decade ago
Simple:
A's work = x.
B's work = y = 3x.
Hence acc. to ques.: 3x - x = 60 ;.
x=30 A's.
y=90 B's.
Now.... 1/30 + 1/90 = 1/z.
z = 90/4 Answer.
A's work = x.
B's work = y = 3x.
Hence acc. to ques.: 3x - x = 60 ;.
x=30 A's.
y=90 B's.
Now.... 1/30 + 1/90 = 1/z.
z = 90/4 Answer.
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 ?
Similarly why don't we take difference of time 60 days B takes 60*3 is 180 days. Please explain to me ?
Dhananjay said:
3 years ago
3x-x = 60,
x = 30.
A=90 B=30.
LCM(90,30) == 90unit.
for A -------> 1unit/day.
for B ------->3unit/day.
Total unit of work = 90/4 = 22.5.
x = 30.
A=90 B=30.
LCM(90,30) == 90unit.
for A -------> 1unit/day.
for B ------->3unit/day.
Total unit of work = 90/4 = 22.5.
(147)
Bharathi said:
2 decades ago
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.
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.
Rajat singh said:
1 decade ago
Simple solution:
a = 3b.
a-b = 60 (difference of b).
3b-b = 60.
b = 30, a = 90.
So they can together work in 1/30+1/90 = 4/90.
:->22.50.
a = 3b.
a-b = 60 (difference of b).
3b-b = 60.
b = 30, a = 90.
So they can together work in 1/30+1/90 = 4/90.
:->22.50.
Mohit jain said:
1 decade ago
Let,
A takes = x days.
B will take = 3x days.
Difference 3x-x = 60.
So 2x = 60.
x = 30 days.
Thus A can do it in 30 days and B in 90 days.
A takes = x days.
B will take = 3x days.
Difference 3x-x = 60.
So 2x = 60.
x = 30 days.
Thus A can do it in 30 days and B in 90 days.
Sanky said:
5 years ago
A:B = 1:3.
B = 3A.
Difference is 60days,
therefore B - A = 60,
3A - A = 60,
2A = 60,
A = 30 & thus B = 90.
Now, 1/30 + 1/90 = 22.5.
B = 3A.
Difference is 60days,
therefore B - A = 60,
3A - A = 60,
2A = 60,
A = 30 & thus B = 90.
Now, 1/30 + 1/90 = 22.5.
Atharv Pathak said:
5 years ago
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.
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.
(1)
Priya said:
1 decade ago
No need to do all that simply guess numbers 30 & 90 which is satisfying this then without using pen we can get answer 22.5 days.
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