For every X, the action [X] is defined: [X] is the greatest integer less than or equal to X. What is the value of [6.5] x [2/3] + [2] x 7.2 + [8.4] - 6.5?  Choose one: A) 12.6. B) 14.4. C) 15.8. D) 15.7. E) 16.4.
[6.5] x [2/3] + [2] x 7.2 + [8.4] - 6.5   = 6*0 + 2*7.2 + 8 - 6.5   = 0 +14.4 +1.5   15.7   Answer 15.7.
<result>D</result>
For every X, the action [X] is defined: [X] is the greatest integer less than or equal to X. What is the value of [6.5] x [2/3] + [2] x 7.2 + [8.4] - 6.5?