In recent year a letter to europe from the united states cost $0.94 to mail. a letter mailed within united states cost $0.44. nancy mailed 5 letters for $3.70 some to europe and some to the united states. how many letters did she send to europe

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

4 candies

step-by-step explanation:

7 x 28 = 196

200 - 196 = 4 candies remaining.