Question 661362
Let {{{ x }}} = the number of comics she started with
She sold half, so then she had half left, or {{{ x/2 }}}
Then she bought {{{ 16 }}}, and she had {{{ x/2 + 16 }}}
You are given that 
{{{ x/2 + 16 = 36 }}}
Now multiply both sides by {{{ 2 }}}
{{{ x + 32 = 72 }}}
{{{ x = 72 - 32 }}}
{{{ x = 40 }}}
She started with 40 comics
check:
She sold half and had 20 left
Then she added 16 making 36 comics
OK