Final answer:
Christopher will calculate his commission by multiplying the sale price of the stereo system ($1,200) by the commission rate (6%) converted to a decimal (0.06), which results in a $72 commission.
Step-by-step explanation:
To calculate the commission Christopher will earn on selling a $1,200 stereo system at a rate of 6%, we need to use the formula:
Commission = Sale Price × Commission Rate
First, convert the commission rate from a percentage to a decimal by dividing by 100. So, 6% becomes 0.06. Then, multiply the sale price of the stereo system by this decimal:
Commission = $1,200 × 0.06
Commission = $72
Therefore, Christopher will earn a commission of $72 for selling the stereo system.