Answer:
Option c (21.4%) is the right approach.
Explanation:
As we know.
On applying the formula:
⇒ [tex]SD \ Portfolio = [wA^2\times SDA^2+wB^2\times SDB^2+2\times wA\times wB\times SDA\times SDB\times Cor(A,B)]^{0.5}[/tex]
On substituting the values, we get
⇒ [tex](0.29^2\times 39^2+0.71^2\times 20^2+2\times 0.29\times 0.71\times 39\times 20\times 0.4)^{0.5}[/tex]
⇒ [tex]21.40 \ Percent[/tex] (%)