Question 638494
The formula for the total logs in the pile of
{{{ n }}} layers with {{{6}}} logs on top seems to
be {{{ (n + 5)*n = n^2 + 5n }}}
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Since there are {{{ 4n + 110 }}} logs in the pile,
{{{ n^2 + 5n = 4n + 110 }}}
{{{ n^2 + n - 110 = 0 }}}
Looking at this, I get
{{{ ( n + 11 )*( n - 10 ) = 0 }}}
{{{ n = 10 }}} ( reject the negative result ) 
There are 10 layers
check:
{{{ 4n + 110 = 4*10 + 110 }}}
{{{ 4n + 110 = 150 }}}
and
{{{ n^2 + 5n = 100 + 50 }}}
{{{ n^2 + 5n = 150 }}}