You ride a bicycle at a speed of 18 miles per hour. I am 3 miles behind my friend. My friend rides a bicycle at a speed of 12 miles per hour. How long does it take to reach your friend?

i think 9 but 6 could also be right

Step-by-step explanation:

18-12=618-3=1515-3=1212-3=9

answer: 1, 3 and 5 are correct

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