What is the average (arithmetic mean) of all multiples of 10 from 10 to 300 inclusive?  Choose one.
A) 155
B) 195
C) 200
D) 205
E) 210
This question can be solved with the Average Formula and 'bunching.'   We're asked for the average of all of the multiples of 10 from 10 to 300, inclusive.   To start, we can figure out the total number of terms rather easily:   1(10) = 10   2(10) = 20   ...   30(10) = 300   So we know that there are 30 total numbers.   We can now figure out the SUM of those numbers with 'bunching':   10 + 300= 
<gadget id="calculator">10 + 300</gadget>
<output>310</output>
310   20 + 290= 
<gadget id="calculator">20 + 290</gadget>
<output>310</output>
310   30 + 280= 
<gadget id="calculator">30 + 280</gadget>
<output>310</output>
310   Etc.   Since there are 30 total terms, this pattern will create 15 'pairs' of 310.   Thus, since the average= (Sum of terms)/(Number of terms), we have...   (15)(310)/(30) =155   155nswer : 155
<result>A</result>
What is the average (arithmetic mean) of all multiples of 10 from 10 to 300 inclusive?