Aptitude - Time and Work - Discussion

Discussion Forum : Time and Work - General Questions (Q.No. 27)
27.
A can finish a work in 24 days, B in 9 days and C in 12 days. B and C start the work but are forced to leave after 3 days. The remaining work was done by A in:
5 days
6 days
10 days
10 1 days
2
Answer: Option
Explanation:

(B + C)'s 1 day's work = 1 + 1 = 7 .
9 12 36

Work done by B and C in 3 days = 7 x 3 = 7 .
36 12

Remaining work = 1 - 7 = 5 .
12 12

Now, 1 work is done by A in 1 day.
24

So, 5 work is done by A in 24 x 5 = 10 days.
12 12

Discussion:
17 comments Page 1 of 2.

Anonymous said:   3 years ago
It is very simple,

Work done By B and C in first 3 days = 7/12,
Work Done by A in 1 day = 1/24,
Hence, 7/12 + n(1/24) = 1 where n represents number of days.
On solving, n = 24-14 = 10 days.
(1)

Student said:   3 years ago
Yes, you are correct Thanks @Shilpi.

Himanshu said:   3 years ago
A = 24.
B = 9.
C = 12.

Take LCM of 24, 9, 12=72.

Now, we will find how much work done in a day,
A = 72/24 = 3per day.

B = 72/9 = 8per day.
C = 72/12 = 6per day.


B+C = 14, from above.
B and Cwork for 3 days, so,

3*14 = 42.
Total work 72.
42 work is already done by B and C.
Remaining work 72-42 = 30.
Now,
A will complete 30 work,so

A is doing 3 work in a day, from above
So 30/3=10 days
(2)

Arun said:   6 years ago
5 women can do a work in 36 days. If ratio b/w the capacity of men and women is 1:3 then find how many day it will take 5 men to complete the same work? Please solve this.

Banodai said:   6 years ago
A can do a work = 1/24.
B can do a work = 1/9.
C can do a work = 1/12.

Whole work have done,
T/24+3/9+3/12 = 1.
T/24+1/3+1/4 = 1.
T/24+7/12 = 1.
T/24+14/24 = 1.
T+14/24 = 1.
T+14 = 24.
T = 24-14.
T = 10 days

Answer : 10 days.
(1)

Mithun said:   7 years ago
7 * 3/36 + x/24 =1
Because:

(B+C) worked for 3 days + followed by A =1 [total work].

Assume x number of days.
(1)

Shilpi said:   7 years ago
A-24days
B-9days
C-12days.

Days LCM 72.
72/24 = 3.
72/9 = 8.
72/12 = 6.
3, 8, 6are efficiency of ABC.

B + C (do work 3 days) = 8 + 6 = 14 * 3 = 42 total work = 72 - 42 = 30. So A work alone30/3 = 10days.
(2)

Sandra said:   8 years ago
Can anyone explain the last step of 24 * 5/12?
(1)

Innareddy Chilakala said:   8 years ago
A = 24.
B = 9.
C = 12.

B & C started after 3 days they leave (The do only 3 days).

Total work = X.

A joined after 3 days X-3 (He finished the work).

= X-3/24 + 3/9 + 3/12 = 1.

To solve this we get X = 13.

A = X-3.

= 13-3.

= 10 days.

Kavya said:   9 years ago
Total work equal to 1.

But B, C are left after 3 days we have to find remaining work of A?

A Consider as X.

Equation can be written as X/24+3/9+3/12 = 1.

By solving (3X+24+18) /72 = 1.

3X = 72-42.

X = 10.


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