You purchase an iPhone for $599, a case for $49 and a charging station for $61. You charge it to your credit card with an annual interest rate of 19%. How much
interest will you have to pay if you take 3 years to pay off the bill?

$404.13

Step-by-step explanation:

First, you start by adding together 599, 49, and 61, which gives you 709. Then, you want to do 709(1.19) to find the amount he would pay including interest in a year, and your answer is 843.71. You want to next subtract that by 709, so you do 843.71-709, and get 134.71. Finally, since it says 3 years, you have to multiply that by 3, and 134.71(3) gives you your final answer, $404.13. I hope this helped you understand better!

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