Question

An instructor scored a student’s test of 50 questions by giving 2 marks for a right answer and −1 for a wrong answer. If the score is 76, find out the number of right answers.

Answer 1

Here let,

Number of right answers = x

Then, the number of wrong answers = 50 − x

And, scoring logic will be:

Each right answer = +2 marks = 2x

Each wrong answer = −1 mark = −1(50 − x)

So, the Total scores will be:

2x − (50 − x) = 76

2x − 50 + x = 76

2x − x = 76 − 50

3x = 126

x = `126/3`

∴ x = 42

Hence, the number of right answers is 42,

And the number of wrong answers is 50 − 42 = 8.