Question 802321
There is going to be 1 more post than the number of 
spaces between posts. For example, if there were 10 
spaces, there would be 11 posts
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Let {{{ n }}} = the number of {{{ 4 }}} ft spaces
{{{ n + 1 }}} = the number of posts
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Note that {{{ 6 }}} in = {{{ .5 }}} ft
{{{ 4n + .5*( n + 1 ) = 32 }}}
{{{ 4n + .5n + .5 = 32 }}}
{{{ 4.5n = 31.5 }}}
{{{ n = 7 }}}
{{{ n+ 1 = 8 }}}
He will use 8 posts
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check:
{{{ 4n + .5*( n + 1 ) = 32 }}}
{{{ 4*7 + .5*8 = 32 }}}
{{{ 28 + 4 = 32 }}}
{{{ 32 = 32 }}}
OK