Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 3)
3.
A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?
Answer: Option
Explanation:
| A's 2 day's work = |  |
1 | x 2 |  |
= | 1 | . |
| 20 | 10 |
| (A + B + C)'s 1 day's work = | |
1 | + | 1 | + | 1 | |
= | 6 | = | 1 | . |
| 20 | 30 | 60 | 60 | 10 |
| Work done in 3 days = | |
1 | + | 1 | |
= | 1 | . |
| 10 | 10 | 5 |
| Now, | 1 | work is done in 3 days. |
| 5 |
Whole work will be done in (3 x 5) = 15 days.
Discussion:
357 comments Page 17 of 36.
Shivam said:
10 years ago
Let n be the no. of total days required;
A's one day work = 1/10.
B's = 1/30, C's = 1/60.
So n(1/10)+n/3(1/30+1/60) = 1.
From here, we get n = 15.
A's one day work = 1/10.
B's = 1/30, C's = 1/60.
So n(1/10)+n/3(1/30+1/60) = 1.
From here, we get n = 15.
Sai said:
1 decade ago
I still can't get clarification.
In the question they asked that in every 3rd day of A's work.
But in explanation how can you say for only 3 days.
In the question they asked that in every 3rd day of A's work.
But in explanation how can you say for only 3 days.
Krats said:
1 decade ago
1/5 works is being done in 3 days.
i.e 1 of the 5 parts of work is done in 3 days.
So total there are 5 parts of work which will take 5*3=15 days.
i.e 1 of the 5 parts of work is done in 3 days.
So total there are 5 parts of work which will take 5*3=15 days.
Alan said:
1 decade ago
Work done by A+B+C for 1 day is 1/10.
So work done by them for 3 days should 1/10 + 1/10 + 1/10 = 3/10.
How come its just for 2 days giving 1/5.
So work done by them for 3 days should 1/10 + 1/10 + 1/10 = 3/10.
How come its just for 2 days giving 1/5.
Pakiil said:
7 years ago
The work done in 3 days is 1/5.
So the work remaining is 4/5.
1/5=3 days,
2/5=3 days,
3/5=3 days,
4/5= 3 days,
5/5= 3 days,
The total days=15.
So the work remaining is 4/5.
1/5=3 days,
2/5=3 days,
3/5=3 days,
4/5= 3 days,
5/5= 3 days,
The total days=15.
Surya said:
8 years ago
Usually, we are taking 20 days means 1/20. Then why there finding 2 days work is multiplied by 2?
My thoughts are 1/20*1/2. Please explain me.
My thoughts are 1/20*1/2. Please explain me.
Aaron said:
9 years ago
At the last step 1/5 * 3 we must do reciprocal right?
Or just multiple and get 15 for the sake of the answer in the options. Please tell me.
Or just multiple and get 15 for the sake of the answer in the options. Please tell me.
Disha said:
4 years ago
Every 3 days 1/5 work is done. Then in how many days 1 whole work is done.
Mathematically = 1/5:3::1:x.
3*1/ (1/5) = 3÷1/5= 3*5/1= 3*5= 15.
Mathematically = 1/5:3::1:x.
3*1/ (1/5) = 3÷1/5= 3*5/1= 3*5= 15.
Karthik said:
1 decade ago
@Preethi.
3*5 because 1/5*5 gives you 1 which means the work has been completed. So 1/5 is derived for work done in 3 days. Understood ah.
3*5 because 1/5*5 gives you 1 which means the work has been completed. So 1/5 is derived for work done in 3 days. Understood ah.
Subash said:
9 years ago
In 3 days they work is 1/5;
Then remaining work is 1 - 1/5 = 4/5,
So using proportions 1/5 : 45 :: 3 : x.
Get 12days.
+ 3days = 15days.
Then remaining work is 1 - 1/5 = 4/5,
So using proportions 1/5 : 45 :: 3 : x.
Get 12days.
+ 3days = 15days.
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