Fuel economy estimates for automobiles built in a certain year predicted a mean of 26.8 mpg and a standard deviation of 5.2 mpg for highway driving. Assume that a normal distribution can be applied. Within what range are ​68% of the​ automobiles? The range for ​68% of the automobiles is
___ to mpg.

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step-by-step explanation:

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step-by-step explanation:

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204