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 4 of 36.

Sindu said:   1 decade ago
Why in the last step 3 is multiplied with 5?

Nitinkumar said:   1 decade ago
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:   1 decade ago
Nice explanation nikitha:-)

Shreya said:   1 decade ago
I dint get how did you multiply 5*3. It was 1/5 83?

ROSE said:   1 decade ago
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:   1 decade ago
Awesome explanation nikitha! this is Wat I was searching for:-).

Balaram said:   1 decade ago
Thank you everybody for participating in the discussion and making clarification for all my unanticipated doubts.... Nikita Prasad gave good explanation.

Arpit Mathur said:   1 decade ago
Hey please explain why A's 2 day work is taken?

Kumar said:   1 decade ago
Can you please tell me how you get 6/60?

Sindhu said:   1 decade ago
@Baskar

Can you please explain me why do you cross multiply at the end for the answer?


Post your comments here:

Your comments will be displayed after verification.