Assume that 3-month Treasury bills totaling $30 billion were sold in $10,000 denominations at a discount rate of 6.250%. In addition, the Treasury Department sold 6-month bills totaling $28 billion at a discount rate of 6.195\%. a. What is the discount amount for 3-month bills? (Do not round intermediate calculations. Round your final answer to the nearest cent.) b. What is the discount amount for 6-month bills? (Do not round intermediate calculations. Round your final answer to the nearest cent.) c. What is the effective rate for 3-month bills? (Do not round intermediate calculations. Round your final answer to the nearest hundredth percent.) d. What is the effective rate for 6-month bills? (Do not round intermediate calculations. Round your final answer to the nearest hundredth percent.)