Suppose Wesley$$ Publishing's stock has a volatility of $55\%,$ while Addison$$ Printing's stock has a volatility of $30\%.$ If the correlation between these stocks is $15\%,$ what is the volatility of the following portfolios of Addison and$$ Wesley:

a$.100\%$ Addison

b$.75\%$ Addison and $25\%$ Wesley

c$.50\%$ Addison and $50\%$ Wesley