Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 1)
1.
A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the fraction of the work that is left is :
Answer: Option
Explanation:
| A's 1 day's work = | 1 | ; |
| 15 |
| B's 1 day's work = | 1 | ; |
| 20 |
| (A + B)'s 1 day's work = |  |
1 | + | 1 |  |
= | 7 | . |
| 15 | 20 | 60 |
| (A + B)'s 4 day's work = | |
7 | x 4 | |
= | 7 | . |
| 60 | 15 |
| Therefore, Remaining work = | |
1 - | 7 | |
= | 8 | . |
| 15 | 15 |
Discussion:
344 comments Page 7 of 35.
Sasikumar said:
7 years ago
The total work of A& B is = 60.
we can get 60 by taking LCM of it.
A's one day work = 4.
B's one day work = 3.
Both A & B 's one day work=7.
A's 4days work=4*4=16.
B's 4 days work=4*3=12.
So, A&B work=28.
The remaining work=60-28=32.
= 32/60,
= 8/15.
we can get 60 by taking LCM of it.
A's one day work = 4.
B's one day work = 3.
Both A & B 's one day work=7.
A's 4days work=4*4=16.
B's 4 days work=4*3=12.
So, A&B work=28.
The remaining work=60-28=32.
= 32/60,
= 8/15.
SRI HARSHA.P said:
1 decade ago
The way said by swetha is very long process.
that wastes time in the exam hall.
thats not the good way to do the problem.
always prepare for ashort method.
Short method takes time for the first time by practice it gives u TIME MANAGEMENT. So better to practice SM.
that wastes time in the exam hall.
thats not the good way to do the problem.
always prepare for ashort method.
Short method takes time for the first time by practice it gives u TIME MANAGEMENT. So better to practice SM.
Arun said:
9 years ago
Harry is correct.
Hi @Deepa, leave that 1-7/15 & %method, simply total efficiency is 7/day, no of worked together is 4, then multiply it becomes 28.
Subtract from total work done 60 - 28 = 32. To find the answer for ques-> 32/60 = 8/15. Cool.
Hi @Deepa, leave that 1-7/15 & %method, simply total efficiency is 7/day, no of worked together is 4, then multiply it becomes 28.
Subtract from total work done 60 - 28 = 32. To find the answer for ques-> 32/60 = 8/15. Cool.
Sundar said:
1 decade ago
@Beer Ibrahim
Q: Why (1-7/15) is applied ?
Ans: To calculate the work remaining. Work remaining = 8/15.
Note: From the above answer, we can say 15/8 days required to
complete the remaining work by A and B.
Hope this will help you. Have nice day!
Q: Why (1-7/15) is applied ?
Ans: To calculate the work remaining. Work remaining = 8/15.
Note: From the above answer, we can say 15/8 days required to
complete the remaining work by A and B.
Hope this will help you. Have nice day!
(1)
Mittal said:
1 decade ago
Plzz solve this A and B can together finish a work in 30 days. They worked at it for 20 days and then B let.
The remaining work was done by A alone in 20 more days. B alone can do the entire work in.
(a) 48 days (b) 50 days (c) 54 days (d) 60 days.
The remaining work was done by A alone in 20 more days. B alone can do the entire work in.
(a) 48 days (b) 50 days (c) 54 days (d) 60 days.
Ammu said:
8 years ago
A's 1 day work = 1/15.
B's 1 day work = 1/20.
Together for 1 day=(1/15+1/20),
=(4+3)/60,
=7/60.
together for 4 days=(7/60) * 4,
= 7/15.
If total work is 1.
Then the rest is = 1 - 7/15,
= 8/15.
B's 1 day work = 1/20.
Together for 1 day=(1/15+1/20),
=(4+3)/60,
=7/60.
together for 4 days=(7/60) * 4,
= 7/15.
If total work is 1.
Then the rest is = 1 - 7/15,
= 8/15.
Syam said:
6 months ago
@Sree.
15 is written as = 5 * 3 and 20 is written as 2^2 *5 then 5 is the common then from 15 take 3 and 20 take 2 square, then 4*3*5=60 then 1 * 4/15 * 4 = 4/60 and for 1/20 =1 * 3/20 * 3 = 3/60.
Then the final answer is 4/60 + 3/60 = 7/60.
15 is written as = 5 * 3 and 20 is written as 2^2 *5 then 5 is the common then from 15 take 3 and 20 take 2 square, then 4*3*5=60 then 1 * 4/15 * 4 = 4/60 and for 1/20 =1 * 3/20 * 3 = 3/60.
Then the final answer is 4/60 + 3/60 = 7/60.
(10)
Shilambarasu said:
1 decade ago
I take LCM for a and b 15, 20 = 60. Now I take per day work a and b.
a = 15*4 and b = 20*3.
So both together work 60/7.
Then I less 4 day work 4*7 = 28. So 60-28 = 32.
Therefore 32/7 or 4.567. This is right or wrong please explain.
a = 15*4 and b = 20*3.
So both together work 60/7.
Then I less 4 day work 4*7 = 28. So 60-28 = 32.
Therefore 32/7 or 4.567. This is right or wrong please explain.
Asi ganesh said:
8 years ago
Why sub (1-7/15)?
I can explain
7/15 is A, B are together work in 4 days
Then question is remaining work is nothing but left this work is total work is 1 and remaining work is is nothing but all of you know
(1-7/15)=8/15.
I can explain
7/15 is A, B are together work in 4 days
Then question is remaining work is nothing but left this work is total work is 1 and remaining work is is nothing but all of you know
(1-7/15)=8/15.
Raj said:
1 decade ago
Can anyone explain answer for the below please?
A and B can together do a piece of work in 30 days. B alone can do it in 40 days. A alone can do it in ? days.
For me its coming 120 days. But in TNPSC ans is 140 days. please explain.
A and B can together do a piece of work in 30 days. B alone can do it in 40 days. A alone can do it in ? days.
For me its coming 120 days. But in TNPSC ans is 140 days. please explain.
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