Question

An insurance agent receives 15% of the cost of each insurance policy she sells

Answer 1

In this question there are several important information's provided. Using these information's it is easy to get the answer to the question asked. Firstly it is already informed that the insurance agent gets a commission of 15% of the policy price for every policy sold. The agent sells a policy of $300.
Now we can write the equation as:
15% of $300 = [(15/100) * 300] dollars
                     = ( 15 * 3) dollars
                     = 45 dollars
So the agent gets a commission of $45 for selling a policy worth $300