Sarah the Sub is the worst substitute teacher. She just can’t seem to get her students under control. But she is getting better...Last year Sarah got tied up & hung upside down by students 89 times. This year it only happened 74 times. What was the percent decrease in the number of times Sarah was tied up & hung upside down?Round to the nearest percent. A).16% C)18%
B).17% D).19%

-4

step-by-step explanation:

answer: it is d

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