Write down an expression for the candidate's total mark in terms of q and c. Write down and solve an equation for the number of questions which james gets right

Question

In a multiple choice examination of 25 questions, four marks are given for each correct answer and two marks are deducted for each wrong answer. A candidate attempts q questions and gets c correct..... james attempts 22 questions and scores 55 marks.

Answer 1

On any test I have taken SAT, GRE, etc

that deducts >1 for a wrong answer - an unattempted question is -1

 

M = marks earned = 55

Q = total questions = 25
      marks per question = 4

T = total marks = 100

q = questions attempted = 22

c = correct answers

 

The question says

" four marks are given for each correct answer and

          two marks are deducted for each wrong answer"

M = 4 marks for a correct  -  2 extra for attempted but wrong

        (c)4 -(q-c)2

-or-

taking away marks from 100 possible instead of adding from zero

M = 100 possible - 4 each unattempted  - 6 each attempted but wrong

       100 -(Q-q)4 -(q-c)6