The price of gas was $2.49 last month. This month, gas costs $2.79. What is the percent increase?

12%

Step-by-step explanation:

2.79 - 2.49 = $0.30

0.30 / 2.49 = 0.12 = 12% (decimal changes to percent)

You can check your work by doing original cost times the decimal of the percent increase. $2.49 * 0.12 = $0.30. Add this to original -> 0.30 + 2.49 = $2.79.  

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