Rock Solid Bank and Trust (RSB&T) offers only checking accounts. Customers can write checks and use a network of automated teller machines. RSB&T earns revenue by investing the money deposited; currently, it averages 6.20 percent annually on its investments of those deposits. To compete with larger banks, RSB&T pays depositors 0.50 percent on all deposits. A recent study classified the bank's annual operating costs into four activities. Activity Using ATM Visiting branch Processing transaction Managing functions Total overhead Cost Driver Number of uses Number of visits Cost $ 3,000,000 Driver Volume 4,000,000 uses 1,800,000 Number of transactions Total deposits 13,200,000 12,000,000 $30,000,000 300,000 visits 160,000,000 transactions $750,000,000 in deposits Data on two representative customers follow. Customer A Customer B ATM uses 100 200 Branch visits 5 Number of transactions Average deposit 40 20 1,500 $6,000 $6,000