Chirag was conducting an experiment in which the average of 11 observation came to be 90. Average of first five observation was 87, and that of the last five was 84. What was the measure of the 6th observation?	Choose the most appropriate option
A) 165 B) 125 C) 145 D) 135 E) None of these
Explanation :   11 * 90 - 5 * 87 - 5 * 84 = 900 - 435 - 420 = 135.   Answer : 135
<result>D</result>
Chirag was conducting an experiment in which the average of 11 observation came to be 90. Average of first five observation was 87, and that of the last five was 84. What was the measure of the 6th observation?