20 is what percent of 50? a. 40% b. 10% c. 250% d. 30%

20 is 40% percent of 50. 20/50 = x/100; 0.4 = x/100; x = 0.4 * 100; x = 40

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