If 7/w + 7/x = 7/y and wx = y, then the average (arithmetic mean) of w and x is Select the correct option:  A) 1/2  B) 1  C) 2  D) 4  E) 8
Given: 7/w + 7/x = 7/ywx=y   Find: (w+x)/2 = ?   7(1/w + 1/x) = 7(1/y) - divide both sides by 7   (1/w + 1/x) = 1/y   (x+w)/wx = 1/wx - sub'd in y=wx   x+w - 1 = 0   x+w = 1   Therefore (w+x)/2 = 1/2   1/2ns: 1/2
<result>A</result>
If 7/w + 7/x = 7/y and wx = y, then the average (arithmetic mean) of w and x is