Question 1099349
<pre><font size=6><b> 1.  A &#8835; B
 2.  A &#8835; (B &#8835; C)
 3.  B &#8835; (C &#8835; D)      /&#8756; A &#8835; D

                   |4.  A          ACP
                   |5.  B        1,4, MP
                   |6.  B &#8835; C    2,4, MP
                   |7.  C        6,5, MP
                   |8.  C &#8835; D    3,5, MP
                   |9.  D        8,7, MP
10. A &#8835; D                        4-9 CP

Edwin</pre>                 </pre></font>