The Treasury Department sold $7.6 billion in new three-month bills at an average discount rate of 7%, down from 7.05% last week. Another $7.6 billion was sold in new six-month bills at an average discount rate of 7.01%, down from 7.02% last week. The three-month rate was the lowest since 6.81% on Sept. 23. The six-month rate was the lowest since 7% on July 8. The new discount rates understate the actual return to investors--7.22% for three-month bills and 7.37% for six-month bills. The discount rate reflects the price discount received when government securities are purchased at less than face value.