Answer : Option A

Explanation :

 I.    (10 x 6) men can complete the work in 1 day.

 1 man's 1 day's work =\(\frac { 1 } { 60 }\)

II  .\( [10*\frac { 24} {7 } ]\)men +\( [10*\frac { 24} {7 } ]\)women can complete the work in 1 day

\(( \frac {2 40 } { 7} )\)men's 1 day work +\(( \frac {2 40 } { 7} )\)women's 1 day work = 1

\([ \frac {2 40 } { 7} \)\(*\frac {1} {60 } ]\)+\(( \frac {2 40 } { 7} )\)women's 1 day's work = 1

\(( \frac {2 40 } { 7} )\)women's 1 day's work =[1-\(\frac { 4 } { 7 } \)]=\(\frac {3 } { 7 } \)

 10 women's 1 day's work =[\(\frac {3 } { 7 } *\)\(\frac {7 } { 240 } *10]\)=\(\frac { 1 } { 8 } \)

So, 10 women can finish the work in 8 days.

III. (10 men's work for 3 days) + (10 women's work for 4 days) = 1

       (10 x 3) men's 1 day's work + (10 x 4) women's 1 day's work = 1

       30 men's 1 day's work + 40 women's 1 day's work = 1

      Thus, I and III will give us the answer.     

      And, II and III will give us the answer