How many three-digit numbers ABC, in which A, B, and C are each digits, satisfy the equation 2B = A + C? Choose the correct option
A) 33  B) 36  C) 41  D) 45  E) 50
Possible solutions are   Diff of 0 --   111,222,........,999 = 9   Diff of 1 --   123, 234, ....., 789 =7x2 = 14   Diff of 2 --   135, 246.......579 = 5x2 = 10   Diff of 3 --   147,258,369 = 3x2 = 6   Diff of 4 --   159 = 1x2 = 2   Last   210, 420,630,840 = 4   So total is 9+14+10+6+2+4= 
<gadget id="calculator">9+14+10+6+2+4</gadget>
<output>45</output>
45.   ANSWER:45
<result>D</result>
How many three-digit numbers ABC, in which A, B, and C are each digits, satisfy the equation 2B = A + C?