The ratio of the areas of two squares is 9: 1, the ratio of their perimeter is:

Correct option is B

let a and b be the sides of the square,

then as per the question

a²  / b² = 9/1 $$\implies$$​  (a/b)²  ⟹ 3²/1 ⟹ a/b = 3/1

Therefore

Ratio of the perimeters of the squares =

4a/4b = a/b = 3/1

Thus the required ratio is 3: 1 

Hence, the correct option is b