I believe this is how you solve it
Answer:
2.25
Step-by-step explanation:
The total frequency is:
20 + 12 + 6 + 2 = 40
Calculate the probability of each score:
P(X=3) = 20/40 = 0.50
P(X=2) = 12/40 = 0.30
P(X=1) = 6/40 = 0.15
P(X=0) = 2/40 = 0.05
So the expected value is:
E = (3)(0.50) + (2)(0.30) + (1)(0.15) + (0)(0.05)
E = 2.25
Since area is length times width, it would be the factors of the equation for the area.
X2+11x+28 factors into...
Length is x+7 so...
Width is x+4
Her chances for the drawings is 1/40 as if it was out of 100, it would be 1/20.
