shoppers enter hamilton place mall at an average of 120 per hour what is the probability that at least 20 shoppers

This question is incomplete, the complete question is;

Shoppers enter Hamilton place mall at an average of 120 per hour

what is the probability that at least 20 shoppers but no more than 23 shoppers enter the  mall between noon and 12:30 p.m.?

the probability that at least 20 shoppers but no more than 23 shoppers enter the  mall between noon and 12:30 p.m

is 4.20787 × 10⁻⁸ ≈ 0.0000000420787  

Step-by-step explanation:

the probability that at least 20 shoppers but no more than 23 shoppers enter the  mall between noon and 12:30 p.m;

interval between noon and 12:30 is 30min

now the shoppers enter an average of  [(120 × 30) / 60] = 60 per 30min

so

P( 20 ≤ X ≥ 23 ) = P( X=20 ) + P( X=21 ) + P( X=22 ) + P( X=23 )

= [(e⁻⁶⁰(60)²⁰) / 20!] + [(e⁻⁶⁰(60)²¹) / 21!] + [(e⁻⁶⁰(60)²²) / 22!] + [(e⁻⁶⁰(60)²³) / 23!]

= [1.3159 × 10⁻⁹] + [3.7598 × 10⁻⁹] + [1.0254 × 10⁻⁸] + [2.6749 × 10⁻⁸]

= 4.20787 × 10⁻⁸ ≈ 0.0000000420787  

therefore the probability that at least 20 shoppers but no more than 23 shoppers enter the  mall between noon and 12:30 p.m is 4.20787 × 10⁻⁸ ≈ 0.0000000420787  

starting with:    

5 + x - 12 = 2x - 7   

5 + x - 12 - x = 2x - 7 - x (subtract x from both sides)   

5 - 12 = x - 7 (combine and cancel x's from both sides)   

5 - 12 + 7 = x - 7 + 7 (add 7 to both sides)   

0 = x (add numbers together on both sides)       

so in order for the equation to be true, x must be 0.   

trying x = -0.5   

5 + x - 12 = 2x - 7 (original equation)   

5 + -0.5 - 12 = 2(-0.5) - 7 (plug in value of x)   

5 + -0.5 - 12 = -1 - 7 (did multiplication)   

-7.5 = -8 (did addition on both sides)       

since -7.5 is obviously not equal to -8, the value of -0.5 for x is wrong.   

trying x = 0   

5 + x - 12 = 2x - 7 (original equation)   

5 + 0 - 12 = 2(0) - 7 (plug in value of x)   

5 + 0 - 12 = 0 - 7 (did multiplication)   

-7 = -7 (did addition on both sides)       

since -7 equals -7, that demonstrates that the value of 0 for x is correct.   

trying x = 1   

5 + x - 12 = 2x - 7 (original equation)   

5 + 1 - 12 = 2(1) - 7 (plug in value of x)   

5 + 1 - 12 = 2 - 7 (did multiplication)   

-6 = -5 (did addition on both sides)       

since -6 is obviously not equal to -5, the value of 1 for x is wrong.