12. a fruit basket contains oranges and grapefruits. one-third of the orange
and one-fourth of the grapefruits were spoiled. you threw away 4 oranges
and 7 grapefruits. how many pieces of fruit were in the basket?

There were 12 + 28 = 40 pieces of fruit in the basket.

Step-by-step explanation:

Suppose there were x oranges and y grapefruit.

Then we have

1 /3 x =  4

x = 4*3 = 12.

1/4 y = 7

y = 7*4 = 28.

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