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 1 of 11.

Vijay said:   1 year ago
4m + 6w = 1/8 -------------------(1)
3m + 7w = 1/10 ------------------(2)

Then (1) *3 & (2)*4.

12m + 18w = 3/8 -------->(3)
12m + 28w = 4/10 ------> (4)

(4)-(3).
You will get 10w=1/40

Therefore, 40 days is the answer.
(57)

Devyani said:   4 years ago
(4 Men + 6 Women)*8= work ----> (1) eqn.
(3 Men + 7 Women)*10= work ----> (2) eqn.

Equating eq. (1) &(1) we get,
32Men + 48 women = Work,
30Men + 70 women = work.

Arrange it in,
32men + 48women=30men + 70women
32-30 men = 70-48 women
2 men = 22 women
1 men = 22/2 women
1 men = 11 women.

Therefore, we get.
Men =11 , Women = 1.
Putting this values in eq. (1).

Therefore,
(4*11+6*1) *8 = work.
Work = 400.

Now,
We know that 10 women's can do the work.

Therefore,
400 work = 10 women.
Work = 10/400 women.
Work = 1/40 women.

That means,

10 women complete the work in 40 days.
(29)

Nayana said:   5 years ago
@All. The Shortcut method:

4m 6w =8days -> 1
3m 7w = 10day -> 2.

(4m+6w)8 = (3m+7w)10
32m+48w = 30m +70w
32m-30m = 70w-48w.

2m = 22w
1m = 11w ---> (3).

Substitute (3) in (1) or(2)

Eq(2)Converting men to women
(3m+7w)10.
((3*11w)+7w)10 = 10x.
40*10 = 10x.
x = 400/10.
x = 40.
Hope it is helpful.
(18)

Likitha Ganta said:   2 years ago
Given:

4m + 6w = 8 days ---> (1)
3m + 7w = 10 days ---> (2)

Total work = Efficiency × days.

By solving equation (1) and (2).
(4m + 6w) × 8 = (3m + 7w) × 10.
16m + 24w = 15m + 35w,
16m - 15m = 35w - 24w,
m = 11w.

Total work = (4 × 11 + 6) × 8.
Total work = 400 unit.
Time taken by 10 women = 400/10.
Time taken by 10 women = 40 days.
(17)

Hemaharshini T said:   2 years ago
4m + 6w = 8 days.
3m + 7w = 10 days.
10w = Tdays.

4m + 6w = 1/8days --->(1)
3m + 7w = 1/10days ----> (2)
10w = Tdays ----> (3)

1st step is to find the value of m and w with (1)&(2)
32m + 48w = 30m + 70w.
32m - 30m = 70w - 48w.
m/w = 22/2.
m = 11 w = 1.

By product method;
(2)=(3).. you can also take (1) instead of (2).
mw*T = mw*T.
[3(11) + 7(1)] * 10 = 10 * T.
400 = 10T.
T = 40days.
(12)

Karthikeyan said:   4 years ago
4x+6y=1/8 ------> (1)
3x+7y=1/10 ----> (2).

Eqn 1 divided by 3.
Eqn 2 divided by 4.
12x+18y=3/8----(3).
12x+28y=4/10---(4).
-------------------------
-10y=1/40.
Y=1/40*10.
y=1/400.

Y value substitute in eqn (1).
4x+6(1/400) =1/8,
4x+6/400=1/8,
4x=1/8-6/400,
4x=44/400,
X=44/400*4,
X=11/400.

1 women complete a work=1/400*10.
1/40.
Hence, 10 women
(11)

Khyati mehta said:   4 years ago
Men=m, Women = w.

4m+6w = 1/8 so 32m + 48w = 1 ---> (1)
3m+7w = 1/10 so 30m + 70w = 1 ---> (2)

Now find the relation between m and w by equating 1 and 2.
We get m=11w.
Now put it in equation 1 we get;
4m+6w.
4*(11w)+6w.
50w complete work in 8 days.
10w complete work in (8*50)/10 = 40 days.
(7)

Urvashi said:   1 year ago
4m+6w=8 days.
3m+7w=10 days.
10w=?
(4m+6w)=1/8.
(3m+7w)=1/10.

Now,
32m + 48w = 30m + 70w.
2m = 22w
2/22 * m = Bawa
2/22 = w/m.
so, w=2 and m=22,
again,
(4m+6w)*8=(10w)*x.
(4*22+6*2)*8=(10*2)*x.
800=20x.
x=40 answer.
(7)

Varshini said:   5 years ago
@All.

Please let me know.

How come x=11/400 and y=1/400?

Anybody explain.
(4)

Ankur Tanwar said:   1 decade ago
Ok I didn't see all the example but I tried and found the following the easiest.

Men= x, Women= y.
So
(4x + 6y) will all the work in ? ans= 8 days (Given).

Then work done by (4x+6y) in 1 day = 1/8 (eq 1) simple, right ?).

Similarly we will get 3x+7y = 1/10... (eq 2).

Now if we can find out the amount of work done by 1 women (i.e - Y) then we can easily find out work done by 10 ?

2 eq

4x + 6 y = 1/8

3x + 7y = 1/10 Now think if we can eliminate X from the eq

Hmm.. Multiply eq 1 by 3 i.e 3* (4x + 6y = 1/8)

Multiply eq 2 by 4 i.e 4* (3x + 7y = 1/10)

We will get?

12x + 18y = 3/8.

12x + 28y = 4/10 or 12x + 28 y = 2/5 .

subtract them . X is gone :D

28y-18y = 2/5 - 3/8

=> 10y= 16-15/40

=> 10y= 1/40

=> y = 1/400 ( This is all we wanted ) .

1 women (i.e y ) can do 1/400 of work.

10 women will do in ? 10*1/400 = 1/40.

Actually 40 days! done.
(3)


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