Question

10. 4 men or 6 women can do a work in 42 days. The number of days 12 men and 3 women would take
to finish the work is
a. 20 days
c. 12 days
b. 15 days
d. 10 days​

Answer 1

Let the men and women together be know as people.

So, 10 people can do work in 42 days.

15 people can do work in 'x' days

If the no. of people increases the work days decreases...

Hence, no. of people and the work days are inversely proportional....

10×42 = 'x' × 15

x = 10×42 / 15

x = 2×42 / 3

x = 2×14

x = 28 days

Hence the answer is 28 days please check the options again the 20 days might be 28 days

Please mark me the brainliest I have no brainliest answers...

Answer 2

According to the question :

Let the work done by 1 man in 1 day be

' a '.

Work done by 1 women in 1 day ' b '.

So, 4a = 6b

=> b = 4a / 6

=> $\sf\large\underline\blue{b\:=\:2a/3}$......... $\sf\large\underline\red{(\:1\:st\:equation\:)}$

4 mens 1 day work :

=> 4a

=> 4a = 1 / 42

=> a = 1 / 4 × 42

=> $\sf\large\underline\blue{a\:=\:1/168}$......... $\sf\large\underline\red{(\:2\: nd\:equation\:)}$

Substituting ( 1 ) and ( 2 ) :

12 men's and 3 women's 1 day work is,

☞ 12a + 3b

=> 12a + ( substituting ' b ' value of 1 st )

=> 12a + 2a

=> 14a ( substituting ' a ' value of 2 nd )

=> 14a = 1 / 168

=> a = 168 / 14

=> a = 1 / 12.

=> $\sf\large\underline\blue{a\:=\:12}$

Total work will be

completed in 12 days.