In a small snack shop, the average (arithmetic mean) revenue was $400 per day over a 10-day period. During this period, if the average daily revenue was $360 for the first 6 days, what was the average daily revenue for the last 4 days? Select:
A) $420
B) $440
C) $450
D) $460
E) $480
The average revenue was $400 per day over a 10-day period --&gt; total revenue over 10-day period is 10*$400=$4,000;   The average daily revenue was $360 for the first 6 days --&gt; total revenue for the first 6 days is 6*$360=2,160;   Total revenue for the last 4 days is $4,000-2,160=$1,840;   Average daily revenue for the last 4 days is $1,840/4=$460.   Answer: $460.
<result>D</result>
In a small snack shop, the average (arithmetic mean) revenue was $400 per day over a 10-day period. During this period, if the average daily revenue was $360 for the first 6 days, what was the average daily revenue for the last 4 days?