The beginning balance of zerina's savings account for the month of july was $1800 and it remained this way for the first 12 days of the month. on july 13, zerina made a withdrawal of $400, so her balance changed, and it remained the same for a total of 8 days. on july 21, zerina made a deposit of $1200, so her balance changed again, and it remained the same for 11 days to finish out the month. if zerina's savings account has an apr of 7.3%, calculates interest daily, and pays interest at the end of the month, how much did zernia earn in interest in the month of july?