The average of nine numbers is 17. The average of first four numbers is 20 and the average of last four numbers is 16. What is the middle number?
Select the correct option:
A) A)7
B) B)8
C) C)9
D) D)10
E) E)11
The total of nine numbers = 9X17 = 153   The total of first 4 and last 4 numbers is = 4 X 20+4 X 16 = 144   So, the middle number is  (153 - 144 )= 
<gadget id="calculator"> (153 - 144 )</gadget>
<output>9</output>
9   9
<result>C</result>
The average of nine numbers is 17. The average of first four numbers is 20 and the average of last four numbers is 16. What is the middle number?