In objective test a correct answer score 4 marks and on a wrong answer 2 marks are deducted. A student scores 480 marks from 150 question. How many answer were correct? options
1)120 2)130 3)110 4)150

• ans. 2
  
  Let x be the correct ans.
  and 150-x be the wrong ans.
  so now
  4x-(150-x)2=480
  if we solve that we get x=130
  
  so ans. is 130
• 11 years agoHelpfull: Yes(1) No(0)
• 2) 130
  
  
  let a = correct answers , b = wrong answers
  
  => a + b = 150 ----------------(1)
  and (4a - 2b) = 480----------(2)
  
  solving (1) and (2),
  => a = 130, b = 20
  
  => 130 were right
  
  
• 11 years agoHelpfull: Yes(0) No(0)
• let "x" be the no. of correctly answered questions and "y" be the wrongly answered ones. then the total no. of questions answered is given by x+y=150
  and the total score is given by 4x-2y=480
  henced, solving these two equations, we'll get "x=130" and "y=20"
  so, 130 answers were correct.
• 11 years agoHelpfull: Yes(0) No(0)