Equation :
This parabola is facing downwards and highest point of the parabola is it's vertex.
Highest point is (-2,2)
so the vertex is (-2,2)
The graph is passing through (-1,0)
Equation in vertex form is


Substitute back in Equation

the graph has two x intercepts -1 and -3
that means (x+1) and (x+3) are the factors
multiply factors to get the equation in standard form

-2x^2-8x-6=0
Answer: 3/8
Step-by-step explanation: Divide 3 ft by 8
The proportion of buses traveling more than 900 miles would be 0.0485; multiply this by the total number of buses and you will have your answer.
We find the z-score associated with 900 miles:
z = (X - μ)/σ = (900-830.11)/42.19 = 1.66
Using a z-table (http://www.z-table.com) we see that the area under the curve to the left of this, less than this, is 0.9515. This means that the area under the curve to the right of this, greater than this, would be 1-0.9515 = 0.0485.