1) If our accounts receivable has increased from $100 at the start of the year to $300 at the end of the year, and if we have sold $1000 worth of merchandise during the year, all on account (i.e., for credit), how much cash have we collected from our customers during the year?

2) If our prepaid rent account has increased from $30 at the start of the year to $50 at the end of the year, and if we have incurred $120 in rent expense during the year, how much cash have we paid to our landlord(s)?