Answer:
$545
Explanation:
Commission is basically the percentage of the profit made that the salesperson gets to keep. The weekly salary is a fixed amount, so that won't change.
Here, Mae Ling sells $4200 worth of merch, which is the profit made, so the commission will be 5% of that:
5% * 4200
Remember that % is just "out of 100", so 5% = 5/100:
(5/100) * 4200 = $210
Add this to the salary:
335 + 210 = $545
She would make $545.