Q. If a person is sitting in a exam having 30 questions (objective type) the examiner use the formula to calculate the score is S=30+4c-w here c is number of correct answer and w is number of wrong answer , the examiner find the score is more than 80, tell how may questions are correct ? if the score is little less but still more than 80 then u wont be able to answer.

• According to the question
  
  S = 30 + 4c - w-----(1)
  [where c is number of correct answer and w is number of wrong answer]
  
  Total number of questions = 30
  w + c = 30
  w = 30 - c -------(2)
  From equation (1) & (2)
  S = 30 + 4c - w
  80 = 30 + 4c - (30 - c)
  80 = 4c + c
  5c = 80
  c = 16
  From equation (2)
  w = 30 - c
  w = 30 - 16
  w = 14
  so number of correct answer(c) = 16 (minimum), 30 (maximum)
  number of wrong answer(w) = 14 (maximum), 0 (minimum)
  
• 11 years agoHelpfull: Yes(32) No(1)
• S=30+4c-w=80
  or 4c-w=50
  also c+w=30
  add both 5c=80
  c=16,w=4
  
  c=16
  w=14
• 11 years agoHelpfull: Yes(5) No(2)
• if S=80
  S=30+4c-w=80
  or 4c-w=50
  also c+w=30
  add both 5c=80
  c=16,w=14
  
  if c=17,w=13,S=30+68-13=85
  as score is more than 80 , so person gets 85 after c=16,w=14
• 11 years agoHelpfull: Yes(0) No(2)