Question

Ms. Ki uses skill builders to help studentsneeding additional practice. Each skillbuilder has a total of 40 questions. Write anequation that can be used to determine y,the percent grade, with x correct answers.

Answer 1

If the skill builder has a total of 40 questions, and the maximum percent grade is 100%, we can use a rule of three to determine the relation between the percent grade y and the number of correct answers x:

$\begin{gathered} 40\text{ correct answers}\to100\text{\%} \\ x\text{ correct answers}\to y \\ \\ \frac{40}{x}=\frac{100}{y} \\ 40y=100x \\ y=\frac{100x}{40} \\ y=2.5x \end{gathered}$

So the equation is y = 2.5x + 0.

(Each correct answer is worth 2.5% of the grade)