Question 916724
he receives 5% <u>of the profit</u> .... on any sales he generates
a) $400 + .05(4000) = $600
b) (857.31 - 400)/.05 = $9146.20 , the profit generated on sales sold that week 
....
In real life best to understand if there is no profit generated on weekly sales...
that would result in receiving  $400 per week