Question 1068558
Money from the boundary hours:
{{{12*35=420}}}
420 dollars, before earning at the higher rate.


{{{492-420=72}}}------the money earned after the first 420 dollars, this $72 at the higher rate.
{{{72/18=4}}}
4 hours at this $18/hour rate.


Total hours worked
{{{cross(12+4=highlight(16))}}}----mistook 35 and 12
{{{35+4=highlight(39)}}}