The average of 17 numbers is 10.9. If the average of first nine numbers is 10.5 and that of the last nine numbers is 11.4, the middle number is  Pick one
A) 11.8	B) 11.4	C) 10.9	D) 11.7	E) 11.9
Sum of first nine numbers (N1 to N9) + Sum of last nine numbers (N9 to N17) = 10.5 x 9 + 11.4 x 9 = 21.9 x 9 = 197.1   Hence, the middle number   = 197.1 - 17 x 10.9   = 197.1 - 185.3= 
<gadget id="calculator">197.1 - 185.3</gadget>
<output>11.8</output>
11.8   11.8NSWER:11.8
<result>A</result>
The average of 17 numbers is 10.9. If the average of first nine numbers is 10.5 and that of the last nine numbers is 11.4, the middle number is