Traditional Method – Let total no. of men = X and Total population be 100.

Total women = (100 − X)

Married men = 40 X/100 …(i) and Married women = (100 − X) × 30/100 …(ii)

But, No. of married men = No. of married women. (as per conditions given)

So, from (i) and (ii) X = 300/7

So, married Men = 300/7 X 40/100 = 120/7 and Married women = 120/7.

Total married population = Men + Women = 240/7

Required percentage = 240/7 % = 342/7 %. So the correct option is (c).

Alternative method: No man marries more than one woman and no woman marries more than one man. It means the Number of married men = Number of married women = 120 (let). Married adult population = 240.

Number of men = 120×100/40 = 300 and Number of women 120 × 100/30 = 400. So, total population = 300 + 400 = 700.

Required percentage 240×100/700 = = 240/7 % = 342/7 %