Question 935829
From 12:05 to 1:05 the clock chimes:
{{{ 2 + 4 + 6 + 8 = 20 }}} plus zero for the hour
From 1:05 to 2:05 the clock chimes:
{{{ 20 }}} plus {{{ 1 }}} for the hour
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In a {{{ 24 }}} hr period, it chimes:
{{{ 24*20 = 480 }}} plus 
2*( 1 + 2 + 3 + 4 + . . . + 11 )
This is:
{{{ 480 + 2*( n )*( n+ 1 ) / 2 }}}
where {{{ n = 11 }}}
{{{ 480 + ( 2*11*12 ) / 2 = 480 + 132 }}}
{{{ 480 + 132 = 612 }}}
The clock chimes 612 times in 24 hours