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 5 of 29.
Nagu said:
2 decades ago
Hi Bharathi,
If A takes 10 days to complete a work means
A's one day work is 1/10
so complete this work A takes 10/1 days is same as 10 days
Sat the same way (A + B)'s 1 day's work 2/45 means
They will take 45/2 = 22 1/2 days
I think you got my point
have a nice day
If A takes 10 days to complete a work means
A's one day work is 1/10
so complete this work A takes 10/1 days is same as 10 days
Sat the same way (A + B)'s 1 day's work 2/45 means
They will take 45/2 = 22 1/2 days
I think you got my point
have a nice day
SHEETAL said:
2 decades ago
Hi Guys,
Don't be confused in data given in question.
I have one short cut to solve such kind of question.
A is K times as good a worker as B & takes X days less than B to finish the work. Then the amount of time required by A & B working together is K * X / K'S SQUARE - 1.
SO IN QUESTION K IS 3. X IS 60. SO PUTTING THE VALUES IN ABOVE MENTIONED FORMULA.
K * X / K'S SQUARE - 1
=3 * 60 / 9 - 1
=3 * 60 / 8
=180 / 8
=22.5 DAYS
AS MENTIONED OPTION B.
I HOPE U WILL UNDERSTAND THIS THING & WILL APPLY IN QUESTION BASED ON THIS.
All the best. Have nice day!
Don't be confused in data given in question.
I have one short cut to solve such kind of question.
A is K times as good a worker as B & takes X days less than B to finish the work. Then the amount of time required by A & B working together is K * X / K'S SQUARE - 1.
SO IN QUESTION K IS 3. X IS 60. SO PUTTING THE VALUES IN ABOVE MENTIONED FORMULA.
K * X / K'S SQUARE - 1
=3 * 60 / 9 - 1
=3 * 60 / 8
=180 / 8
=22.5 DAYS
AS MENTIONED OPTION B.
I HOPE U WILL UNDERSTAND THIS THING & WILL APPLY IN QUESTION BASED ON THIS.
All the best. Have nice day!
Sangeetha said:
2 decades ago
Oh thanks sheetal
Prashant said:
1 decade ago
Suppose B takes x days to finish the work and then according to question A will take (60-x) days to work. in question the ratio of time taken is 1:3 therefore
1/3= (60-x)/x
x=45
So A can complete the work in (60-x)=(60-45)=15 days
So (A+B) one day's work
=(1/15 + 1/45)
=4/45
So (A+B) complete the work in 45/4 = 11 1/4 days.
1/3= (60-x)/x
x=45
So A can complete the work in (60-x)=(60-45)=15 days
So (A+B) one day's work
=(1/15 + 1/45)
=4/45
So (A+B) complete the work in 45/4 = 11 1/4 days.
Sugumaran said:
1 decade ago
Ratio of time taken=1:3
A finish the work in 60 days and B in x days.
1:3::60:x
x=180 days
So,
A and B 1'days work 1/60+1/180=45 days
Is it correct or not?
A finish the work in 60 days and B in x days.
1:3::60:x
x=180 days
So,
A and B 1'days work 1/60+1/180=45 days
Is it correct or not?
M.Atul said:
1 decade ago
@Sugumaran please read carrefully problem. Though you have got same answer but it doesn't satisfied second condition that differnce in day should be 60 not 120.
Priya said:
1 decade ago
Please tell me why we are taking 3/2 to multiply with 60. Please explin me.
Harsha said:
1 decade ago
A clear approach:
Given: A's time taken:B's time taken=1:3
So A's proportion of time taken=1/(1+3)=>1/4*some x
B's proportion of time taken=3/(1+3)=>3/4*some x
As it is said that difference of time is 60 days
B's time-A's time=60
=> 3x/4-x/4=60
=>x=120
So A's proportion of time taken =x/4=120/4=30 days
B's proportion of time taken =3x/4=3*120/4=90 days
A's 1 day's work = 1/30
B's 1 day's work = 1/90
(A + B)'s 1 day's work = (1/30 + 1/90)= 4/90=2/45
A and B together can do the work in 45/2 = 22 1/2 days.
Given: A's time taken:B's time taken=1:3
So A's proportion of time taken=1/(1+3)=>1/4*some x
B's proportion of time taken=3/(1+3)=>3/4*some x
As it is said that difference of time is 60 days
B's time-A's time=60
=> 3x/4-x/4=60
=>x=120
So A's proportion of time taken =x/4=120/4=30 days
B's proportion of time taken =3x/4=3*120/4=90 days
A's 1 day's work = 1/30
B's 1 day's work = 1/90
(A + B)'s 1 day's work = (1/30 + 1/90)= 4/90=2/45
A and B together can do the work in 45/2 = 22 1/2 days.
Naveen said:
1 decade ago
Hi, in prashanth answer, he equals the ratio 1/3 to 60-x/x but it actually x-60/x.
Shilpi said:
1 decade ago
Can you pls teach me this equation
1/30+1/90=4/90
1/30+1/90=4/90
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