11. stunt problem:
the formula s = v2ld relates a stunt car driver's speeds in miles per hour at the beginning of a skid
to the length d of the skid in feet. a stunt driver must skid her car to a stop just in front of a wall. when
the driver starts her skid, she is travelling at 64 mi/hr and is 200 feet from the wall. when the driver
comes to a stop, how many feet will be between her car and the wall? round to the nearest foot.

b

2

−

b

b

3

+

7

b

2

+

14

b

+

6

%

−

3

b

3

+

7

b

2

+

14

b

+

6

%

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

2

step-by-step explanation: