MASTER AMENDMENT AND AGREEMENT

     This Master Amendment and Agreement (this "Agreement") is entered into as
of this 22nd day of May, 1996 by and among the selling entities set forth on
the signature pages attached hereto (each entity being referred to herein as a
"Seller" and collectively as the "Sellers") and ERP Operating Limited
Partnership, an Illinois limited partnership ("Purchaser").

                                R E C I T A L S

     A.   Each Seller and the Purchaser have entered into an Agreement of Sale
dated as of April 23, 1996 (herein called the "Purchase Agreement") for the
sale by such Seller to Purchaser of certain property described therein.  All
capitalized terms which are used herein but which are not otherwise defined
herein shall have the meaning ascribed to such term in the applicable Purchase
Agreement.

     B.   Each Purchase Agreement provides that during the Approval Period,
Purchaser shall have the right to review the status of title of the Property
(including, determining what endorsements, if any, the Title Insurer will make
available to Purchaser).

     C.   Each Purchase Agreement further provides that each Seller will
deliver to Purchaser an Updated Survey and Purchaser shall have ten (10) days
from the date of receipt of the Updated Survey to approve the Updated Survey. 

     D.   Purchaser has reviewed the status of title for each Property and has
reviewed certain of the Updated Surveys; provided, however, Purchaser and
Seller have not yet agreed upon "Permitted Exceptions" for each Property.

     E.   Purchaser and Seller desire to amend each Purchase Agreement to give
Purchaser and Seller until May 23, 1996 to agree upon Permitted Exceptions for
each Property.

     NOW, THEREFORE, for and in consideration of the sum of Ten Dollars
($10.00) and other good and valuable consideration, the receipt and sufficiency
of which is hereby acknowledged, each Seller (with respect to the Purchase
Agreement to which such Seller is a party) and the Purchaser, hereby agree as
follows: 

                               A G R E E M E N T


     1.   RECITALS.  The recitals set forth above are hereby incorporated
herein by reference as if same were fully set forth herein.

     2.   AMENDMENT.   Purchaser and Seller hereby agree that Purchaser and
Seller shall have until the later of: (i) the expiration of the Approval Period
(as same may have been extended) or (ii) May 23, 1996 (the "Deadline Date") to
agree upon Permitted Exceptions for each Purchase Agreement (subject to
Purchaser's additional right to have 10 days to review Updated Surveys).  If
Purchaser and Seller are unable to agree upon Permitted Exceptions on or prior
to the Deadline Date, then Seller shall have the right to elect to either
terminate the applicable Purchase Agreement, in which case the applicable
Earnest Money, including interest thereon, shall be returned to Purchaser
immediately following the applicable Seller's receipt of the Reports or (ii)
agree to cure the title objections identified by Purchaser as being
problematic, which cure may be effectuated by causing the Title Insurer, at
such Seller's expense, to insure over any objection, if applicable.

     3.   Miscellaneous

          A.   Except as modified herein, each Purchase Agreement shall remain
unmodified and in full force and effect. 

          B.  This Amendment may be executed in any number of counterparts,
each of which shall be deemed an original but all of which shall constitute one
and the same instrument. 

     IN WITNESS WHEREOF, the undersigned have executed this Agreement as of the
date and year first above written.


                              PURCHASER

                         ERP OPERATING LIMITED PARTNERSHIP,
                         an Illinois limited partnership

                         By:  Equity Residential Properties Trust,
                              a Maryland real estate investment
                              trust

                              By: /s/Daniel L. Baskes
                                 ----------------------------------
                              Name: Daniel L. Baskes
                                   --------------------------------
                              Title: Attorney
                                    -------------------------------

                         Lakeville Resort Apartments

                         LAKEVILLE INVESTORS, an Illinois joint venture

                         By:  Balcor Realty Investors 85- Series III A Real
                              Estate Limited Partnership, a partner in
                              Lakeville Investors

                              By:  Balcor Partners-XVIII, an Illinois general
                                   partnership, its general partner

                                   By:  The Balcor Company, a Delaware
                                        corporation, a general partner


                                        By: /s/Alan Lieberman
                                           -----------------------------
                                        Name:  Alan Lieberman
                                        Its: Senior Vice President

                         By:  Lakeville Partners, an Illinois limited
                              partnership, a partner in Lakeville Investors

                              By:  Balcor Partners-XIX, an Illinois general
                                   partnership, its general partner

                                   By:  The Balcor Company, a Delaware
                                        corporation, a general partner


                                        By: /s/Alan Lieberman
                                           ------------------------------
                                        Name:  Alan Lieberman
                                        Its: Senior Vice President

                              Park Place II Apartments

                              PLYMOUTH PLACE ASSOCIATES, an Illinois limited
                              partnership

                              By:  Balcor Partners-XVIII, an Illinois general
                                   partnership, its general partner

                                   By:  The Balcor Company, a Delaware
                                        corporation, a general partner


                                        By: /s/Alan Lieberman
                                           -----------------------------
                                        Name:  Alan Lieberman
                                        Its:   Senior Vice President

                              Country Ridge Apartments

                              Country Ridge Associates, an Illinois limited
                              partnership

                              By:  Balcor Partners-XVIII, an Illinois general
                                   partnership, its general partner

                                   By:  The Balcor Company, a Delaware
                                        corporation, a general partner


                                        By: /s/Alan Lieberman
                                           --------------------------------
                                        Name:  Alan Lieberman
                                        Its:   Senior Vice President