Question

Henry predicted whether he got answers right or wrong in his 50 question exam.

He identified the 31 questions he thought he got right.
It turns out that Henry got 6 questions wrong that he thought he got correct and he only got 12 of the questions wrong he had predicted.
What is the percentage accuracy he had with predicting his scores?

Answer 1

Henry predicted that he got 31 questions right, but he actually got 31 - 6 = 25 questions right.

Henry predicted that he got 19 questions wrong, but he actually got 12 questions wrong.

Therefore, Henry predicted that he would get 31 + 19 = 50 questions, but he actually got 25 + 12 = 37 questions correct.

To find the percentage accuracy of Henry's predictions, we can use the formula:

percentage accuracy = (number of correct predictions / total number of predictions) x 100%

In this case, the number of correct predictions is 37 out of 50, since Henry got 37 questions right out of the 50 total questions. The total number of predictions is 50, since Henry predicted the outcome of all 50 questions.

Using the formula, we get:

percentage accuracy = (37 / 50) x 100% = 74%

Therefore, Henry had a prediction accuracy of 74%.