Answer:
(D) P(AUB) = 0.65
Step-by-step explanation:
Since A and B are independent:
P(A ^ B) 
= P(A) × P(B)
= 0.3 × 0.5 = 0.15
P(AUB) = P(A) + P(B) - P(A^B)
= 0.3 + 0.5 - 0.15
= 0.65
 
        
             
        
        
        
Of course A does because integers are positive and negative
        
             
        
        
        
First, all the heights have to be converted to similar units, say feet.
Therefore,
Building= 20 feet
Tree = 252*0.083333 = 21 feet
Flagpole = 6*3 = 18 feet
The tallest of the three is the tree and thus should cast the longest shadow. However, it should be noted that at exactly noon when the sun is overhead, all the three will have equal length of shadow (that is, 0 feet long).
        
             
        
        
        
Use the sine function.
sine = opposite side of triangle divided by the hypotenuse.
Here is the set up:
sin(50°) = BC/3
sin(50°)/3 = BC
Use your calculator to simply left side. 
Take it from here.