Just by the number of hours she worked, she will earn:
$8 x 8 = $64
She also gets a 5% comission for all merchandise she sells over $200.
$420 - $200 = $220
Thus, the amount which she sold over $200 is $220.
5% x $220 = $11
Hence, the total amount she earned for that day is:
$64 + $11 = $75