Dr. Robbins took the elevator to the 18th floor. He went back down 7 floors, up 2 floors, and down 5 floors. What floor is he now on? And please tell him to stop playing with the elevators. * 5 points

the 8th floor

Step-by-step explanation:

you just add and subtract so 18-7 +2 -5 = 8

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