An artist can sell 20 compies of a painting for $100 each, but for each additional copy he makes the value of each painting will go down by 1 dollar. How many copies should he make to maximize the profit?

40 copies for $3000

Step-by-step explanation:

First: The Equation

y=(20+x)(100-x)

This shows how for every new painting, the price will go down.

y=2000+80x-x²

Convert it to standard form: ax²+bx+c

You can now choose to graph it or find the vertex form. For the limit of time, I will just use a graph.

The vertex, (40,3000), is your answer, where the x value is the number of paintings and the y value the money made.

your answer would be 10x - 1

mr. flanders’ class sold 47 doughnuts and   mr. rodriquez’s class sold 38 cartons of milk

step-by-step explanation:

let x be the number of doughnuts sold by mr. flanders’ class and y be the number of cartons sold by mr. rodriquez’s class.

1. together, the classes sold 85 items, then

x+y=85.

2. both classes earn earned $104.49 for their school. if doughnuts were sold for $1.35 each, then x doughnuts costed $1.35x. if cartons of milk were sold for $1.08 each, then y cartons costed $1.08y. hence,

1.35x+1.08y=104.49.

3. solve the system of two equations: