1. ## Substitution problem

Problem Solving: What do the variables represent; when does cost=revenue.
A high school class is putting together a newsletter. The cost of the design and colour copies is $200 plus 75 cents per copy. The class plans to sell the newsletter for$1.25. The cost and revenue can be represented by the following system of equations.

Cost: C=200+0.75n

Revenue: C=1.25n

Solve the system of equations by substitution.

I know the answer but im not sure how to get to it. Any help is apprectiated.

2. Originally Posted by lovalente
Problem Solving: What do the variables represent; when does cost=revenue.
A high school class is putting together a newsletter. The cost of the design and colour copies is $200 plus 75 cents per copy. The class plans to sell the newsletter for$1.25. The cost and revenue can be represented by the following system of equations.

Cost: C=200+0.75n

Revenue: C=1.25n

Solve the system of equations by substitution.

I know the answer but im not sure how to get to it. Any help is apprectiated.
Set the two equations equal to each other:

\displaystyle \begin{aligned} 1.25n &= 200 + 0.75n \\ 0.5n &= 200 \\ n &= 400 \end{aligned}

Now find C by plugging in n = 400 into one of the equations, and you get C = 500.

01

3. Originally Posted by lovalente
Problem Solving: What do the variables represent; when does cost=revenue.
A high school class is putting together a newsletter. The cost of the design and colour copies is $200 plus 75 cents per copy. The class plans to sell the newsletter for$1.25. The cost and revenue can be represented by the following system of equations.

Cost: C=200+0.75n

Revenue: C=1.25n

Solve the system of equations by substitution.

I know the answer but im not sure how to get to it. Any help is apprectiated.
cost equals revenue $\displaystyle \Rightarrow{1.25n=200+0.75n}$