Answer:
2.24
Step-by-step explanation:
The probability formula using a Poisson distribution is:

λ = 90 / 18 = 5 average goals per interval (interval = a game)
So if for example you were interested in the probability of making 2 goals in a game
k = 2

This was just an example,
The standard deviation is 

Let the numbers be x = 5x+18
3(5x+18) + 4x= 16
15x+ 54+ 4x= 16
19x = 16-54
X=-38/19
X= -2
5x+18= 5 × -2+18 = 8
U can do this 2 ways...
26.50 + 0.06(26.50) = 26.50 + 1.59 = 28.09 <==
or
1.06(26.50) = 28.09 <=
There are infinity of fractions equal to 1/2, it just means half of a number, so for example, 3/6, 4/8, 5/10, 6/12 are all equal to 1/2 and so on