What is the average (arithmetic mean) of all the multiples of ten from 10 to 80 inclusive? Choose the correct choice from the following answers:
A) 20
B) 45
C) 100
D) 105
E) 110
The multiples of ten from 10 to 80 inclusive would be an evenly spaced set with 8 terms - 10, 20, 30,.......80   So average = (First term + Last Term)/2 = (10 + 80)/2 = 90/2= 
<gadget id="calculator">90/2</gadget>
<output>45</output>
45   Hence, the correct answer is 45.
<result>B</result>
What is the average (arithmetic mean) of all the multiples of ten from 10 to 80 inclusive?