Westinghouse Electric said it will purchase up to 10 million of its 152.2 million shares of outstanding stock through the open market or through private purchases . . . China reported that contracts for foreign investment in China fell to $1.24 billion, a drop of 20%, compared to the first half of 1985 . . . The Alameda Times-Star has been sold to Alameda Newspapers, which owns three other Alameda County newspapers including the Daily Review in Hayward, Calif.