A city water tank holds 20 gallons of water. A technician empties 25% of the tank. How many more gallons of water must be removed from the tank so that it has 2/5 of the water that it started with? The technician must remove blank amount of
more gallons of water for the tank to have 2/5 of the water that it started with.

add an !

step-by-step explanation:

$5.41

step-by-step explanation:

$20 - $14.51 = $5.49.

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