July $3$ Joan provides lawn services to Sally$$s repair shop on account, $$300.$

July $6$ One of Joan$$s mowers malfunctions. Sally provides repair services to Joan on account, $$250.$

July $9$ Sally pays $$300$ to Joan for lawn services provided on July $3.$

July $14$ Sally borrows $$400$ from Joan by signing a note.

July $18$ Joan purchases advertising in a local newspaper for the remainder of July and pays cash, $$120.$

July $20$ Joan pays $$250$ to Sally for services provided on July $6.$

July $27$ Sally performs repair services for other customers for cash, $$600.$

July $30$ Sally pays employee salaries for the month, $$100.$

July $31$ Sally pays $$400$ to Joan for money borrowed on July $14.$