Answer:
d
Step-by-step explanation:
because
 
        
             
        
        
        
Would be the last answer because (n-3)times (n-3) is n^2-6n+9
        
             
        
        
        
The probability that the train will be there when Alex arrives is 5/18
If Alex arrives at any time after 1.20pm the chances that train will  be there is 1/3.
However  if alex arrives at 1.00pm exactly there is no chance the train will be arrive there.
The probability that the train will be there increase linearly to 1/3 as alex's arrival time moves from 1.00pm to 1.20pm.
By arranging the probabilities over the first 20 minutes to get a 1/6 chance the train will be there if alex arrives between 1.00pm to 1.20pm 
we get the final answer by 
=1/3( 1/6 + 1/3 + 1/3)
=5/18
So, the probability that the train will be there when Alex arrives is 5/18
Learn more about PROBABILITY here 
brainly.com/question/24756209
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Answer:
14x+42y
Step-by-step explanation:
7(2x+6y)
14x+42y