If fixed costs are $200,000 and the unit contribution margin is $20, what amount of units must be sold in order to have a zero profit

The following information is needed to reconcile the cash balance for gourmet catering services. * a deposit of $5,600 is in transit. * outstanding checks total $1,000. * the book balance is $6,400 at february 28, 2019. * the bookkeeper recorded a $1,800 check as $17,200 in payment of the current month's rent. * the bank balance at february 28, 2019 was $17,410. * a deposit of $400 was credited by the bank for $4,000. * a customer's check for $3,300 was returned for nonsufficient funds. * the bank service charge is $90. what was the adjusted book balance?