Aptitude - Time and Work - Discussion

Discussion Forum : Time and Work - General Questions (Q.No. 12)
12.
4 men and 6 women can complete a work in 8 days, while 3 men and 7 women can complete it in 10 days. In how many days will 10 women complete it?
35
40
45
50
Answer: Option
Explanation:

Let 1 man's 1 day's work = x and 1 woman's 1 day's work = y.

Then, 4x + 6y = 1 and 3x + 7y = 1 .
8 10

Solving the two equations, we get: x = 11 , y = 1
400 400

1 woman's 1 day's work = 1 .
400

10 women's 1 day's work = 1 x 10 = 1 .
400 40

Hence, 10 women will complete the work in 40 days.

Discussion:
106 comments Page 2 of 11.

CHAN said:   1 decade ago
Hi All, Let me explain.

8 * 4x + 6y = 1 ( multiplied by 8)
10* 3x + 7y = 1 (multiplied by 10)

32x + 48y = 1 --(1) ----> (1) * 30
30x + 70y = 1 --(2) ----> (2) * 32

Hence

960x+1440y=30/8 (since 30*32 =960)
960x+2240y=32/10 (same)
----------------
800y=1/400
y = 1/400

By substituting the value of y Eqn (1)

You will get 4x+6/400=1/8

x=11/400

REST ARE IN ABOVE WEBSITE'S EXPLANATION.

ARAVINDHAN said:   1 decade ago
4m+6w=1/8 --(1)

3m+7w=1/10 --(2)

Solve this two we get 10w = 1/40;

So the answer is 40 days.

Karunakaran said:   1 decade ago
Hi Poonam,

Let 1 man's 1 day's work = x and 1 woman's 1 day's work = y.
So 4 man's 1 day's work= 4x and 6 woman's 1 day's work = 6y.
Working together overall work will done in 8 days.
So working together overall work will done in 1 day = 1/8

i.e 4x + 6y = 1/8

So 3 man's 1 day's work= 3x and 7 woman's 1 day's work = 7y.
Working together overall work will done in 10 days.
So working together overall work will done in 1 day = 1/10

i.e 3x + 7y = 1/10

By solving
4x + 6y = 1/8 * 3
3x + 7y = 1/10 * 4
------------------------
12x + 18y = 3/8
12x + 28y =4/10

So 10y = 1/40

y= 1/400
x=11/400

Vijaya said:   1 decade ago
Ok I can understand this problem but I want any shortcut method for doing the problem so fast. Because time is precious in competative exams. Dng all these caluclation is waste of time so I sortcut to this one so plzz any one help me.

Priya said:   1 decade ago
Can any one say shortcut to this problem.

Thank you in advance.

Saleem said:   1 decade ago
how it possible 4x+6/400=1/8

x=11/400

Mr.chan ,could u pls explain

S.p.velu said:   1 decade ago
Can anyone to solve those two equation in step by step?

Ashish said:   1 decade ago
Hi all,
(4m+6w)8 = (3m+7w)10...........eq.(1)
2m = 22w
M = 11W
NOW, we put the value of M in eq. 1
(44+6)8= 10X
X = 400/10
X = 40 Ans.

Jyothi said:   1 decade ago
Hi ashish. Thanks.

Ashish said:   1 decade ago
Hello, Jyothi. It's my pleasure.


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