Shade 12 squares on the 4-by-10 grid.

What percent to is shaded?

On a 10 by 4 grid, there would be 40 squares. If you were to shade 12 of those squares, it can be shown as the fraction:

12/40 = 0.3

to get a percentage, we would have to multiply by 100

30% is to be shaded

30%

Step-by-step explanation:

Total number of squares: 4*10=40

Shaded squares: 12

Fraction of shaded squares: 12/40

If you make the denominator 100, then the numerator is the percentage:

it would take 7/10 of an hour too fill the pool.

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