In objective test a correct ans score 4 marks and on a wrong ans 2 marks are ---. a student score 480 marks from 150 question. how many ans were correct?

a) 120 b) 130 c) 110 d) 150

• let x be the correct answer and y be the wrong answer
  so the total number of questions is (x+y)=150
  =>4x-2y=480
  =>6x=780
  hence x=130
  option b is the answer
• 13 years agoHelpfull: Yes(18) No(6)
• ANSWER (b) 130 (520 - 40)
• 13 years agoHelpfull: Yes(4) No(7)
• Ans. b
  x+y = 150 -----1
  4x-2y = 480 -----2
  
  Multiply by 2 of eq. 2
  
  4x-2y = 480
  2x+2y = 300
  
  6x = 780
  
  x= 130
  
  Ans. b
• 5 years agoHelpfull: Yes(0) No(0)