Question

A test in Science is scored the following way: each correct answer earns 10 points
while each wrong answer earns one point less. In a 30-item test, Rafael got 23 correct
answers and 7 wrong answers. What was his score?

Answer 1

c = correct answers

w = wrong answers

S = score

S = c ∙ 10 - w ∙ 1

S = 10 ∙ c - w = 10 ∙ 23 - 7 = 230 - 7 = 223

Answer 2

don't use it to a venm diagram, it's just a problem solving.