What area of expense is best to target when looking for possible ways to cut back on spending

Seattle bank’s start-up division establishes new branch banks. each branch opens with three tellers. total teller cost per branch is $96,000 per year. the three tellers combined can process up to 90,000 customer transactions per year. if a branch does not attain a volume of at least 60,000 transactions during its first year of operations, it is closed. if the demand for services exceeds 90,000 transactions, an additional teller is hired and the branch is transferred from the start-up division to regular operations. required what is the relevant range of activity for new branch banks