1 QUAKER STATE CORPORATION AND SUBSIDIARIES EXHIBIT 11 Computation of Net Income Per Share (in thousands except per share data, unaudited) Quarter Ended Nine Months Ended 9/30/98 9/30/97 9/30/98 9/30/97 ------- ------- ------- ------- 1. Net income $ 986 $ 5,309 $ 4,379 $21,018 ======= ======= ======= ======= 2. Average number of shares of capital Stock outstanding--Basic 36,430 35,140 36,384 35,042 3. Shares issuable upon exercise of dilutive stock options outstanding during the period, Based on average market prices 245 313 445 214 4. Average number of capital and capital equivalent shares outstanding--Diluted (2 + 3) 36,675 35,453 36,829 35,256 5. Net income per capital and capital equivalent Share - Basic (1 divided by 2) $ 0.03 $ 0.15 $ 0.12 $ 0.60 ======= ======= ======= ======= 6. Net income per capital share assuming full Dilution - Diluted (1 divided by 4) $ 0.03 $ 0.15 $ 0.12 $ 0.60 ======= ======= ======= ======= 19