One of two Montgomery County adults accused of allowing 30 to 50 teenagers to drink alcohol nearly two years ago at a keg party has been found guilty of endangering the welfare of children and furnishing alcohol to minors. The party was held early last year at the Abington home of 46-year-old Kathleen Tompkins, the mother of the 15-year-old boy who hosted the party. She has been given 30 days to 23 months in Montgomery County Prison, and she will be allowed to serve her time on weekends. She and her former boyfriend, 51-year-old Daniel McIntyre of Upper Dublin, were both charged with similar offenses. He pleaded guilty earlier. Prosecutors say they knew the youths, mostly between the ages of 14 and 16, had a keg of beer in the basement, and they taught the teens drinking games. One boy became so sick from the alcohol he had to be taken to Abington Memorial Hospital for treatment. At her sentencing Wednesday, Judge Paul Tressler said the consequences could have been devastating.