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 6 of 11.

Sharad said:   1 decade ago
@Manu.

4x+6y = 1/8.............1.
3x+7y = 1/10............2.

For canceling term x we can multiply 1 by 3 and equation 2 by 4. Then we got:

12x+18y = 3/4...........3.
12x+28y = 4/10.........4.

Then subtract equation 4 by equation 3.

y = 1/100.
Put y in equation 1.
y = 1/400.

Saurabh said:   1 decade ago
@Narasingarao please explain your method?

Deepika said:   1 decade ago
Please explain how to solve these two equations? Explain with it in step by step?

Raman said:   1 decade ago
Can anyone please solve this by LCM method?

Priya said:   1 decade ago
Can any one solve this by work equivalence (man days) or by normal equation method?

Rishabh nagpal said:   1 decade ago
Don't make it complex, it is so easy.

As given,

4 men and 6 women can do work in 8 days so,

Work done by 4M+6W in 1 day is 1/8.

-> 4M+6W=1/8 -------- (1).

And, work done by 3M and 7W in 1 day is 1/10.

-> 3M+7W=1/10 -------- (2).

Now solve these 2 equations,

Equation (1) *3 different equation (2) *4 to make M equal to solve you will get

10W=1/40.

It means 10W will done work in 40 days.

Bhupendra kumbhare said:   1 decade ago
Hello friends.

Can anyone explain if any other examples in which 3 persons like man, woman and boy replacing by other?

Kavya said:   10 years ago
Given 4m 6w = 8 days.

3m+7w = 10 days.

Next step: (4m+6w) 8 days = 32m+48w.

(3m+7w) 10 days = 30m+70w.

Next step: 32m+48w = 30m+70w.

32m-30m = 70w-48w.

2m = 22w.

2(1m = 11w) therefore 1m = 11w.

Take any relation given in question 4m+6w = 8 days.

4(11)+6w = 44+6 = 50w.

Finally 50w-8 days.

So, 50w*8 days/10w = 40 days.

Gananathan said:   10 years ago
M = 11 W.

4m+6w = 8 -----> 4*11+6 = 50 (women) = 8 (days) /// assume work =1 /////.

10w = ?

Apply formula: Women 1*day 1/work 1 = Women 2*day 2/work 2.

50*8/1 = 10*d2/1.

50*8/10 = d2.

400/10 = d2.

40/1 = d2.

So women do work for 40 days.

Sekhar said:   10 years ago
4 men + 6 women = 8 days.
3 men + 7 women = 10 days.

10 women = ?

8(4 men + 6 women) = 10(3 men + 7 women).
32 men + 48 women = 30 men+70 women.

So 2 men = 22 women. Then 1 man = 11 women.

Now convert men into women. 4 men + 6 women = 8 days.

Now instead of 4 men write 44 women. So 44 women + 6 women = 8 days.

50 women ------- 8 days.
10 women -------- ?

m1 d1 = m2 d2.
50*8 = 10*?

So 10 women can do work in 40 days!


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