Question 1197449
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Hi  
Poisson distribution at a mean rate of Lambda symbol = 0.4 'per hour'.

spend '1 hour' waiting for the ships
{{{P(x, lambda) =( lambda^x)*(e^(-.4*1) )/x! }}}
Using TI or similarly an inexpensive calculator like an Casio fx-115 ES plus
P(2 ≤ x ≤ 4) = P(x=2) + P(x=3) + P(x=4) = .0536 + .007 + .0007


spend '30 minutes' waiting for the ships 
{{{P(x, lambda) =( lambda^x)*(e^(-.4/2) )/x! }}}
P(x ≥ 2) = 1 -  P(x≤ 1) = 1 - (P(x=0) + P(x=1) )
P(x ≥ 2) = 1 -  {{{((.4^0/0!)+(.4^1/1!) *e^(-.4/2))}}} 

spend '2 hours' waiting for the ships 
{{{P(x, lambda) =( lambda^x)*(e^(-lambda*2) )/x! }}}
P( x ≤ 3 ) = P(x=0) + P(x=1) + P(x=2)
p( x ≤ 3) = {{{((.4^0/0!)+(.4^1/1!)+(.4^2/2!)) *e^(-.4*2)}}}
Wish You the Best in your Studies.
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