How many 3-digit integers between 100 and 200 have a digit that is the average (arithmetic mean) of the other 2 digits? Choose the correct choice from the following answers:
A) 1  B) 7  C) 9  D) 11  E) 19
Since the number is between 100 and 200, the hundreds digit has to be 1.   And since the answer choices are small enough, it won't hurt just to write them out. 102, 111, 120, 123, 132, 135, 147, 153, 159, 174, 195.   Answer 11
<result>D</result>
How many 3-digit integers between 100 and 200 have a digit that is the average (arithmetic mean) of the other 2 digits?