Question 1194633
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As the other tutor mentioned, you can form subsets of size 7 by picking subsets of size 2. 
Whatever 2 items you pick, they will be ignored so you can focus on the other 7 items.


Because this value 2 shows up, it may be handy to form a two-way table. In this case, we'll have a 9 row and 9 column two-way table like this.<table border = "1" cellpadding = "5"><tr><td></td><td>87</td><td>92</td><td>93</td><td>93</td><td>94</td><td>94</td><td>95</td><td>96</td><td>97</td></tr><tr><td>87</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>92</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>93</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>93</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>94</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>94</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>95</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>96</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>97</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr></table>


Write X's along the main diagonal. 
This is because we cannot select the same item twice when forming a 2 element subset.
<table border = "1" cellpadding = "5"><tr><td></td><td>87</td><td>92</td><td>93</td><td>93</td><td>94</td><td>94</td><td>95</td><td>96</td><td>97</td></tr><tr><td>87</td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>92</td><td></td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>93</td><td></td><td></td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>93</td><td></td><td></td><td></td><td>X</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>94</td><td></td><td></td><td></td><td></td><td>X</td><td></td><td></td><td></td><td></td></tr><tr><td>94</td><td></td><td></td><td></td><td></td><td></td><td>X</td><td></td><td></td><td></td></tr><tr><td>95</td><td></td><td></td><td></td><td></td><td></td><td></td><td>X</td><td></td><td></td></tr><tr><td>96</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td>X</td><td></td></tr><tr><td>97</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td>X</td></tr></table>
 

We'll also write X's in every entry below the diagonal. 
Why? Notice that stuff below the diagonal mirrors the stuff above the diagonal.
Example: look at row 2, column 1 and you'll see we're dealing with the same values as row 1, column 2. Both of those values being 87 and 92 in either order.
<table border = "1" cellpadding = "5"><tr><td></td><td>87</td><td>92</td><td>93</td><td>93</td><td>94</td><td>94</td><td>95</td><td>96</td><td>97</td></tr><tr><td>87</td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>92</td><td>X</td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>93</td><td>X</td><td>X</td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>93</td><td>X</td><td>X</td><td>X</td><td>X</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>94</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td></td><td></td><td></td><td></td></tr><tr><td>94</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td></td><td></td><td></td></tr><tr><td>95</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td></td><td></td></tr><tr><td>96</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td></td></tr><tr><td>97</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td></tr></table>


The empty cells that haven't been crossed out are then filled with the 7 element subsets
For example, in row 1, column 2 we'll have the subset {93, 93, 94, 94, 95, 96, 97} which is everything except the 87 & 92
<table border = "1" cellpadding = "5"><tr><td></td><td>87</td><td>92</td><td>93</td><td>93</td><td>94</td><td>94</td><td>95</td><td>96</td><td>97</td></tr><tr><td>87</td><td>X</td><td><font size=2>{93, 93, 94, 94, 95, 96, 97}</font></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>92</td><td>X</td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>93</td><td>X</td><td>X</td><td>X</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>93</td><td>X</td><td>X</td><td>X</td><td>X</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>94</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td></td><td></td><td></td><td></td></tr><tr><td>94</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td></td><td></td><td></td></tr><tr><td>95</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td></td><td></td></tr><tr><td>96</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td></td></tr><tr><td>97</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td></tr></table>



I'll let you fill out the rest.


Edit: I realize that there are duplicate entries (93 and 94). I'm not sure if your teacher made a typo or not. I'll keep my answer as is, since it may be useful for similar types of problems of this nature.
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