Upon arrival at Auschwitz, the SS forcibly split the men from the women and children, and Otto Frank was separated from his family. Those deemed able to work were admitted into the camp, and those deemed unfit for labour were immediately killed. Of the 1,019 passengers, 549—including all children younger than 15—were sent directly to the gas chambers. Anne Frank, who had turned 15 three months earlier, was one of the youngest people spared from her transport. She was soon made aware that most people were gassed upon arrival and never learned that the entire group from the "Achterhuis" had survived this selection. She reasoned that her father, in his mid-fifties and not particularly robust, had been killed immediately after they were separated.