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?
Chirag Lakhani said:
(Mon, Jun 14, 2010 11:28:11 PM)
How step 3 is make 1/10+1/10? please explain it.
Vinoth said:
(Thu, Jun 17, 2010 12:00:16 AM)
How do you know total working day is 3 (last step).
Satyendra Sharma said:
(Tue, Jun 29, 2010 01:49:25 AM)
3 days work = 1/5
it means 1 day work =1/15
that is 1/15 work is done in 1 Day
now 4/5 part of work that is (1-1/5) will be done in :15*4/5 =12 days....
Hence total work done will done in (12 + 3 ) days...
Abhishek said:
(Fri, Sep 3, 2010 03:35:01 PM)
@chirag:
Step 3 gives work done in first 3 day i.e. work done in 1st day + work done in 2nd day +work done in 3rd day = 1/20 (by A alone) + 1/20 (by B alone) + 1/10 (done by A, B and C together)
Similarly they continue and as per the question on every 3rd day A is joined by B and C.
Nitesh Nandwana said:
(Fri, Oct 1, 2010 11:05:31 AM)
Hi chirag don't go on step, here our aim is to compute total work done in 3 days once, first 2 days A is working alone and last 3rd day we are adding work's of B and C.
Sushant said:
(Mon, Nov 22, 2010 02:23:29 AM)
(A + B + C)'s 1 day's work = 1 + 1 + 1 = 6 = 1 .
20 30 60 60 10
how did we get 60
Bala said:
(Wed, Nov 24, 2010 03:43:42 AM)
I can't get this.
Vikas said:
(Thu, Dec 9, 2010 05:24:39 AM)
Answer Explained:
A is working alone for two days, 3rd day he is assisted by B and C.
A's 1 day work=1/20
A working on 2 days=2*1/20=1/10
A+B+C working on 3rd day, so 1 day of working together=1/20+1/30+1/60=6/60=1/10
So total work done till 3rd day=1/10+1/10=2/10=1/5
So if in 3 days = 1/5 of work is completed....
Than, 3*5 days = 1/5*5 work will be completed.
=15days
Dhanam said:
(Mon, Dec 20, 2010 06:09:04 AM)
Why are you taking 2 days for first step?
Vishnu said:
(Sat, Dec 25, 2010 08:25:29 AM)
Why you have taken the a+b+c? A is assisted by only B, C know.
Anbu said:
(Wed, Dec 29, 2010 12:07:34 PM)
How you got 6/60.
I think the ans is 12.
Beeribrahim said:
(Fri, Dec 31, 2010 01:30:49 AM)
How it is user
Now, 1 work is done in 3 days.
5
Whole work will be done in (3 x 5) = 15 days.
Shreekanth said:
(Mon, Jan 3, 2011 12:07:52 AM)
@Vishnu...
As per the statement A will do the work three days continuosly but only on third day B & C will assist, so
A's thrid day work must also include with both B & C
that's why...
(A + B + C)'s 1 day's work is taken
Vijay said:
(Fri, Jan 7, 2011 06:44:16 AM)
1/20+1/(30X3)+1/(60X3) = 1/15
Is my way of solving correct?
Nikita Prasad said:
(Fri, Jan 7, 2011 10:31:03 AM)
There's a simple logic friends,
If a person wrks for n days, his 1 day's work is 1/n.
or the other way round,
if 1/n is the 1 day's work then he works for n days.
& it can be very well known if 1 day's work is known it can be multiplied with any numbers of days you wish to.
Similarely,
Here last statement tell the same i.e. 3days work is 1/5,
so to calculate 1 day's work we need to divide it by 3 wiz gives 1/15.
so if 1/15 is 1 day's work then they together work for 15 days.
& the logic behind 2 days & 3 dats work is :
A's 2 days work is (1/20)*2, i.e 1 day's multiplied by nth day.
but on the "3rd day" they all A,B&C work together wiz equals to 1/10.
@chitra
assisted by B and C on every third day
it means A's 2 days + (B&C)'s 1 day
from d 1st explanation u got
Work done in 3 days=(1/10 + 1/10)=1/5
dat is in 3 days=1/5 works
in ques dey ask "In how many days can A do the work"
now cross multiply..
(5*3) days=1 work..
1 work = 15 days...
now u got it ah?
Samathu said:
(Fri, Jan 28, 2011 04:51:10 AM)
Nice explanation baskar.
Munish said:
(Sun, Jan 30, 2011 10:35:10 AM)
Thank you Vikas for your information, I have understood.
Karan Singh said:
(Sat, Feb 5, 2011 03:11:18 AM)
Indeed, the explanation of baskar is correct.
Karan Singh said:
(Sat, Feb 5, 2011 03:15:29 AM)
Is Vijay's formuala correct? In real aptitude test, the quick formula will be handy and faster to calculate.
Manasa said:
(Sun, Feb 6, 2011 09:06:17 AM)
@nikita prasad. You just rock. Good explanation with logic. :-) ).
Poonam said:
(Wed, Feb 9, 2011 10:36:07 AM)
Please give altarnate methad to solve this question, then we know wether the ans you got is right or wrong.
Rajasekhar said:
(Fri, Feb 11, 2011 01:09:27 AM)
The question does'nt mean to find the 3 days work how we can solve this for 3 days work?.
Hamsa said:
(Mon, Feb 21, 2011 03:28:33 AM)
How did you get 6/60 could you please clarify?
Divya said:
(Tue, Mar 8, 2011 07:36:28 AM)
Chitra its very clear.
Suneel Kumar said:
(Mon, Mar 28, 2011 10:59:09 AM)
Why you multiply 3*5?
Manoj Shukla said:
(Wed, Apr 6, 2011 10:11:20 AM)
Why 3*5?
Niket said:
(Thu, Apr 14, 2011 01:18:19 AM)
Actually in 3rd step work done by A on 3rd day was not added that's why the answer became 15 days.
Sindu said:
(Tue, Apr 26, 2011 06:29:40 AM)
Why in the last step 3 is multiplied with 5?
Nitinkumar said:
(Wed, May 4, 2011 08:03:50 AM)
A+B+C=(1/20)+(1/30)+(1/60)=1/10
ON 3 RD DAY HE IS TAKING WORK FROM BOTH B&C HIS 2DAYS WORK +A+B+C WORK= 1/10+1/10 = 2/10 =1/5
MULTIPLY WIT 1/3 U LL GET 1/15
15 DAYS
Ramesh said:
(Mon, May 9, 2011 09:50:21 AM)
Nice explanation nikitha:-)
Shreya said:
(Mon, May 23, 2011 12:38:40 AM)
I dint get how did you multiply 5*3. It was 1/5 83?
Rose said:
(Thu, May 26, 2011 07:56:27 AM)
Work done in 3days=1/10(A'S 2DAYS WORK)+1/10(1DAY WORK FROM ABC)
=2/10=1/5
NOW CROSS MULTIPLY FOR 1/5 3DAYS ARE REQUIRED FOR 5/5 DAYS HOW MANY DAYS ARE REQUIRED
NOW 5/5=1
1*3/1/5=
3*5/1=15
Fathi said:
(Mon, Jun 6, 2011 10:41:27 AM)
Awesome explanation nikitha! this is Wat I was searching for:-).
Balaram said:
(Mon, Jun 27, 2011 11:22:52 PM)
Thank you everybody for participating in the discussion and making clarification for all my unanticipated doubts.... Nikita Prasad gave good explanation.
Arpit Mathur said:
(Sat, Jul 2, 2011 03:45:23 PM)
Hey please explain why A's 2 day work is taken?
Kumar said:
(Mon, Jul 4, 2011 02:36:08 PM)
Can you please tell me how you get 6/60?
Sindhu said:
(Tue, Jul 5, 2011 02:16:38 AM)
@Baskar
Can you please explain me why do you cross multiply at the end for the answer?
Benny said:
(Wed, Jul 6, 2011 05:42:08 AM)
Here my simple ans:
A is working continue 2 day's.So he's 2day's work is:1/20*2=1/10;
in 3rd day he join other two person B and C.So here 3 member work:
1/20+1/30+1/60=1/10;
3 day's work is :1/0+1/10=1/5
So total work done by them is 10+5=15;
Sathish said:
(Sat, Jul 9, 2011 09:58:38 AM)
Hi friends,
we know that whole work completed means we will denote it as 1(full)....
2=1(in 2days full work get completed)
5=1(in 5days full work get completed)
just simple 5=1/2 =>5*2=1(just cross multiple the 2)
Preethi said:
(Sun, Jul 24, 2011 11:49:51 AM)
1/5 of work being done in 3 days. But how do we arrive at the total no. Of days worked by A? what is the logic behind?
Neetu Singh said:
(Fri, Aug 5, 2011 05:28:31 PM)
@benny-reli nice explanation.
Harry said:
(Tue, Aug 9, 2011 07:17:29 AM)
1.)days worked by A is 2; 1 day helped by B and C and not A,
2.)given is A's 3 day work
3.)total 1 day work of A,B,C is find
4.)A's 2 day work is found
Result calculation:
A's 3day work=>(1/10)+(1/10)=>A 2day work+A,B,C's 1days)
=>1/5(of whole work) [5 is n]
A's whole work=3*5=15days
Manoj said:
(Wed, Aug 24, 2011 12:49:04 PM)
i.e;
3 days =1/5
6 days=2/5
9 days=3/5
12 days=4/5
15 days=5/5(1)==work completed
Anil said:
(Sat, Sep 3, 2011 06:16:33 AM)
Thanks benny.
Poornima said:
(Sun, Sep 18, 2011 06:08:38 PM)
How can you taking that 3 days? and 1/10+1/10 what is it ?
Ganbrave said:
(Fri, Sep 23, 2011 09:24:40 PM)
@Poornima
A works for 2 days and B,C joins him on 3rd day.
so total combination of them is now 3days
Based on these 3days we can furthur calculate..ok??
A's 2 days work=1/10 and on 3rd day A,B,C together work=1/10
So sum of them gives u total 3days of work done by all of them.
Imraz said:
(Sat, Sep 24, 2011 01:11:27 AM)
Here 15 days is required for the completion of the work by A, B, C. But in question it is asked 'in how many days can A do the work' - which means the number of days A worked. So to get this we need to divide the 15 by 3 and get '5' as answer.
Can anyone please make me clear if my interpretation is incorrect ?
Rohit said:
(Sat, Sep 24, 2011 12:47:54 PM)
1st day A's + 2nd day A's work = (1/20 + 1/20) = 2/20 = 1/10--(1)
3rd day work is added by B's and C's work so, work done by A+B+C=
(1/20+1/30+1/60) = 1/10--(2)
from (1) and (2)= 1/10+1/10 =1/10
Balalakshmi said:
(Mon, Sep 26, 2011 09:04:22 AM)
Answer explained:
A is working for 2 days alone so A's two day work is first calculated as
A's 2 day work is =1/20*2 = 1/10
Now B and C work with A for only one day(ie 3rd day) and A also working along with B and C in the same 3rd day so A,B and C one day work(ie 3rd day work) is calculated as=(1/20+1/30+1/60)=1/5
Now A's 2 day work+ ABC one day work(ie 3rd day work is calculated)= (1/10+1/10)=1/5
Therefore in 3 days only 1/5 of work is completed
Thus to complete full work 3*5=15 days
(3days=1/5 of full wok completed
3*5 days=full work completed
15 days = full work completed)
Pavethra said:
(Thu, Sep 29, 2011 02:05:32 PM)
I tell that third day alone A join them so on third day it is 1/20 +1/30+1/60=1/10(here a,b,c all work together)
then 2 days A never join them then B and C work together
then SO 1/20 +1/30=1/5
then make it ulta 10+5=15days
easy na.
Yashraj said:
(Mon, Oct 3, 2011 10:26:35 AM)
(1/20) + (1/30) + (1/60) = 6/60. Please explain me this step.
Xyz said:
(Tue, Oct 4, 2011 09:17:13 AM)
@Yashraj
When we want to do (1/20)+(1/30)+(1/60) generally, we take the help of L.C.M, But in above case Highest number is 60 which is Divisible by all the remaining number i.e. 20 and 30.
Hence we take L.C.M. as 60 i.e. (3+2+1)/60 becomes 6/60.
Build your Basic maths Strong My friend.
Rehan said:
(Fri, Oct 14, 2011 07:18:45 AM)
We can consider the avg of the 3 days and calculate for total work only if we know the number of days of their work is a multiple of 3. I mean if they had to work for 14 days, b and c would have assisted them only till day 12. On day 13 and 14 again a would have to work alone.
So how can we take 1/5th of work is done in 3 days?
Mohosin said:
(Mon, Oct 31, 2011 10:03:30 AM)
We can solve it in this way also:
In 1 day, A alone can do 1/20th f the work,
So, in 2 days A can do (1/20 * 2)= 1/10th f the work
On 3rd day A,B and C together do= (1/20 + 1/30 + 1/60)= 6/60= 1/10
___________________________________________________________
Now, after 3 days, total work done= (1/10 + 1/10)=2/10=1/5
so, in 3 days they can complete 1/5th of the work.
so, for completing the whole work, they need (5*3) days= 15days
Kv Manikanta said:
(Wed, Nov 2, 2011 01:50:31 PM)
How do you say that A's work is 2 days it means how it came 2 (1/20) = 1/10.
Hitesh said:
(Tue, Nov 8, 2011 11:06:28 PM)
work done by A per day=1/20;
work done by B per day=1/30;
work done by C per day=1/60;
Let the work is completed in 3x days
So,
1/20*3x+1/30*x+1/60*x=1
=> x=5
=> No. of days required to complete the work=3*5=15days
Anitha said:
(Sat, Nov 12, 2011 09:54:05 PM)
Why we have to calculate A's days work? Explain any one please.
Siddu said:
(Mon, Nov 21, 2011 02:52:33 PM)
Please explain how we will get 6/60 please?
Kamalakannan said:
(Mon, Dec 5, 2011 05:51:26 PM)
Could you tell me? why you take A has done by 2 days work?
Eswarijana said:
(Thu, Dec 22, 2011 12:49:59 AM)
I can't understand the last step.
Renjini said:
(Wed, Jan 4, 2012 05:16:56 PM)
How could get 1/5? I can't understand.
Tania said:
(Sat, Jan 7, 2012 08:50:43 PM)
@kamalakannan
Because A alone does the work in FIRST day and in 3rd day he takes the help of B, C. So 1st A's 2daz work is calculated.
Naari said:
(Thu, Jan 12, 2012 08:48:04 PM)
@vikas.
Good work dude.
Sindhuja said:
(Sun, Feb 5, 2012 08:33:05 AM)
@monoj.
Superb explanation.
Emmanuel said:
(Fri, Feb 10, 2012 05:48:31 AM)
Can someone help me out? why are they multiplying 3 and 5 but not any number for example 3 and 6 making 18 ?
Whole work will be done in (3 x 5) = 15 days.