The standard deviation of Woolworth's share price is $30\%$ and that of Reckon's shares is $30\%.$ When I hold both shares in my portfolio with an equal amount in each, and the returns have a correlation of minus $1,$ the overall standard deviation of returns of the portfolio is:

Question $4$Answer

a$.$

zero.

b$.$

more than $30\%.$

c$.$

Cannot say for sure.

d$.$

unchanged at $30\%.$