Rita makes and sells necklaces. The materials to make each necklace cost $2.75. Last week she made 8 necklaces and wants to make a total profit of $78. Using the equation 8(x+2.75)=78, Rita determined that she needs to sell each necklace for $7 to make a total profit of $78. Which error did Rita make?

Question

Answer:

Rita's error is in the sign of 2.75 in her equation. If x is her selling price, Rita needs to find the value of x in
.. 8(x -2.75) = 78

That value will be
.. x = 2.75 +78/8 = 12.50