Answer:
$120
Step-by-step explanation:
The total revenue brought to the company by this employee is:
$350 + $250 = $600
Since he/she earns a 20% commission on the goods sold, this particular employee will receive:
$600 * 0.2 = $120
*0.2 is the multiplier when it's 20%
In other words, he/she earns $20 out of each $100 in sold goods. Since his/hers total sold goods consist out of 6 factors of $100, the same proportion will apply to the commision, that is $20 * 6 = $120.