Question

Colin predicted whether he got answers right or wrong in his 50 question exam. He identified the 14 questions he thought he got wrong. It turns out that Colin got 5 questions right that he thought he got wrong. Colin also got a total score of 35 out of 50 in the test. What is the percentage accuracy he had with predicting his scores?

Answer 1

Number of questions Colin thought wrong, N = 14.

So, his score by his prediction will be, S = 50-14 = 36.

Now,

Number of questions which are actually wrong, n = 14 -5 = 9.

His actual score, s = 50 - 9 = 41.

Percentage accuracy is given by :

$\%=\dfrac{Actual-Real}{Real }\times 100\\\\\%=\dfrac{41-36}{41}\times 100\\\\\%=12.195\%$

Hence, this is the required solution.