An anti aircraft gun can fire four shots at a time. If the probabilities of the first, second, third and the last shot hitting the enemy aircraft are 0.7, 0.6, 0.5 and 0.4, what is the probability that four shots aimed at an enemy aircraft will bring the aircraft down?	Select the correct option.
A) 0.084  B) 0.916  C) 0.036  D) 0.964  E) 0.92
Sum of probabilities of each shot= 0.7+0.3*0.6+0.3*0.4*0.5+0.3*0.4*0.5*0.4= 
<gadget id="calculator">0.7+0.3*0.6+0.3*0.4*0.5+0.3*0.4*0.5*0.4</gadget>
<output>0.964</output>
0.964   ANSWER:0.964
<result>D</result>
An anti aircraft gun can fire four shots at a time. If the probabilities of the first, second, third and the last shot hitting the enemy aircraft are 0.7, 0.6, 0.5 and 0.4, what is the probability that four shots aimed at an enemy aircraft will bring the aircraft down?