1 EXHIBIT 11 Computation of Net Income Per Share Quaker State Corporation and Subsidiaries For the Years Ended December 31, 1997, 1996 and 1995 (in thousands except per share data, unaudited) 1997 1996 1995 - ---------------------------------------------------------------------------------------------- 1 Net income $23,088 $13,723 $12,100 ============================================================================================== 2 Average number of shares of capital stock outstanding - Basic 35,213 34,352 32,119 3 Shares issuable upon exercise of dilutive stock options outstanding during the period, based on average market prices -- 179 -- 4 Average number of capital and capital equivalent shares outstanding - Diluted (2 + 3) 35,213 34,531 32,119 5 Net income per capital and capital equivalent share - Basic (1 divided by 2) $ 0.66 $ 0.40 $ 0.38 ============================================================================================== 6 Net income per capital share assuming full dilution - Diluted (1 divided by 4) $ 0.66 $ 0.40 $ 0.38 ==============================================================================================