Poison’s Distribution = $\frac{(e^{-p} * p^{x})}{x!}$
No. of request in 60 minutes = 30
No. of request in 1 minute = 0.5
p = No. of request should be made in 40 minutes = 40 * 0.5 = 20
x = But In Reality How many Request in 40 minutes = 0
Poison’s Distribution = $\frac{(e^{-20} * 20^{0})}{0!}$ = $e^{-20}$