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?
12 days
15 days
16 days
18 days
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 36 of 36.

Bala said:   1 decade ago
I can't get this.

Sushant said:   1 decade ago
(A + B + C)'s 1 day's work = 1 + 1 + 1 = 6 = 1 .
20 30 60 60 10

how did we get 60

Nitesh Nandwana said:   1 decade ago
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.

Abhishek said:   1 decade ago
@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.

Satyendra Sharma said:   2 decades ago
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...
(1)

Vinoth said:   2 decades ago
How do you know total working day is 3 (last step).
(1)

Chirag Lakhani said:   2 decades ago
How step 3 is make 1/10+1/10? please explain it.


Post your comments here:

Your comments will be displayed after verification.