Here are returns and standard deviations for four investments.

	Return (%)	Standard Deviation (%)
Treasury bills	4.0	0
Stock P	12.0	11
Stock Q	13.0	28
Stock R	22.0	22

Calculate the standard deviations of the following portfolios.

a. 50% in Treasury bills, 50% in stock P. (Enter your answer as a percent rounded to 2 decimal places.)

b. 50% each in Q and R, assuming the shares have: (Do not round intermediate calculations. Enter your answers as a percent rounded to 2 decimal places.)