Answer:
D. $105
Step-by-step explanation:
Use definition:
[tex]\text{Average of }n\text{ numbers}=\dfrac{\text{The sum of }n\text{ numbers}}{n}[/tex]
The average wage for 15 consecutive days is $91, then by definition
[tex]\$91=\dfrac{\text{The sum of wages for 15 days}}{15}\Rightarrow \\ \\\text{The sum of wages for 15 days}=\$91\cdot 15=\$1,365[/tex]
The average wage for first 7 consecutive days is $87, then by definition
[tex]\$87=\dfrac{\text{The sum of wages for first 7 days}}{7}\Rightarrow \\ \\\text{The sum of wages for first 7 days}=\$87\cdot 7=\$609[/tex]
The average wage for last 7 consecutive days is $93, then by definition
[tex]\$93=\dfrac{\text{The sum of wages for last 7 days}}{7}\Rightarrow \\ \\\text{The sum of wages for last 7 days}=\$93\cdot 7=\$651[/tex]
Now,
[tex]\text{The sum of wages for 15 days}=\text{The sum of wages for first 7 days }+\\ \\+\text{ The wage for 8th day}+\text{The sum of wages for last 7 days}\\ \\\$1,365=\$609+\text{ The wage for 8th day}+\$651\\ \\\text{ The wage for 8th day}=\$1,365-\$609-\$651=\$105[/tex]
