Question

Henry predicted whether he got answers right or wrong in his 50 question exam. He identified the 32 questions he thought he got right. It turns out that Henry got 2 questions wrong that he thought he got correct and he only got 15 of the questions wrong he had predicted. What is the percentage accuracy he had with predicting his scores?

Answer 1

Henry accurately predicted his performance for 45 out of the 50 questions on his exam, which gives him a percentage accuracy of 90% when predicting his exam scores.

Step-by-step explanation:

To calculate the percentage accuracy of Henry's predictions, we need to consider the total number of questions he got correct and compare it to the number he thought he would get correct.

• Henry thought he got 32 questions right, but since he got 2 wrong, this means he actually got 30 questions right. Out of the 18 questions he thought he got wrong (50 total questions - 32 he thought he got right), he actually got 3 right (18-15).

• Therefore, Henry got 30+3 = 33 questions correct in total. The number of correct predictions he made for the questions he got right is 30 (since he missed 2 that he thought were correct) and for questions he got wrong is 15 (since he correctly predicted 15 wrong answers).

• The total number of correct predictions Henry made was 30 (correct) + 15 (wrong) = 45. So, the percentage accuracy of his predictions is (45 correct predictions / 50 total questions) × 100%.

• Percentage Accuracy = (45/50) × 100%
  = 90%

Hence, Henry's percentage accuracy in predicting his exam scores was 90%.

Answer 2

Henry correctly predicted 45 out of 50 questions, giving him a percentage accuracy of 90% in predicting his exam scores.

Step-by-step explanation:

To determine Henry's percentage accuracy in predicting his scores, we need to perform a few calculations based on the information provided. Henry predicted he got 32 questions right. In reality, he got 2 of those wrong, meaning he actually got 30 questions right. He predicted 15 questions wrong and got them wrong, but since there are 50 questions in total, and he got 30 correct, this also means he got 20 wrong in total. Therefore, he predicted 5 wrong questions as right.

The number of correct predictions Henry made was 30 (for right answers) plus 15 (for wrong answers), which adds up to 45 correct predictions out of 50. The formula to calculate percentage accuracy is (number of correct predictions/total number of questions) × 100%.

Percentage accuracy = (45/50) × 100% = 0.9 × 100% = 90%.

Henry's percentage accuracy in predicting his exam scores is 90%.