The average of seven numbers is 21. The average of first three numbers is 19 and the average of last three numbers is 23. What is the middle number?  Choose the correct choice from the following choices: A) 20 B) 22 C) 18 D) 19 E) 21
The total of seven numbers = 7X21 = 147   The total of first 3 and last 3 numbers is = 3 X 19+3 X 23 = 126   So, the middle number is  (147 - 126 )= 
<gadget id="calculator"> (147 - 126 )</gadget>
<output>21</output>
21   21
<result>E</result>
The average of seven numbers is 21. The average of first three numbers is 19 and the average of last three numbers is 23. What is the middle number?