I need help with the Return on Common Stockholders Equity

Net income	$320,000
Preferred dividends	12,800
Average stockholders' equity	2,831,858
Average common stockholders' equity	1,484,058

Determine (a) the return on stockholders equity and (b) the return on common stockholders equity. If required, round your answers to one decimal place.

a. Return on Stockholders' Equity	11.30%
b. Return on Common Stockholders Equity