With an interest period of 1 year, determine the net cash flow at end of year from the cash flows shown: Receipts, Disbursements, Month $1000 $1000 Jan 500 300 Feb 800 500 Mar 200 400 Apr 120 400 May 600 500 June 900 600 July 800 300 Aug 700 300 Sept 900 500 Oct 500 400 Nov 400 400 Dec 1800 700