Jayant gets 3 marks for each right sum and loses 2 marks for each wrong sum. He attempts 30 sums and obtains 40 marks. The number of sums attempted correctly is
(1) 25
(2) 20
(3) 26
(4) 27

• suppose he attempted x sum correctly, then
  
  x*3 -2*(30-x) =40
  5x =100
  x=20
  
  so 20 correct sums... option 2.
  
• 12 years agoHelpfull: Yes(40) No(0)
• simple this is linear eqn in 2 variable
  the Ist eqn
  
  3x - 2y = 40
  
  x + y = 30
  
  solving
  
  x = 20 (right answer)
  y = 10 (wrong answer
• 12 years agoHelpfull: Yes(22) No(1)
• 3x+2y=30
  40 marks for correct ans
  3(40)+2y=30
  y=-10
  so in 30 marks there are 10 wrong ans so 20 correct ans
• 11 years agoHelpfull: Yes(5) No(4)
• number of sums correctly attempted by Jayant are 20
• 12 years agoHelpfull: Yes(3) No(4)
• when he attempt 30 questions 30x3=60
  if he achieve 40 marks 30x3-10x2=40
  
• 11 years agoHelpfull: Yes(3) No(6)
• As per the question x + y = 30 & 3x - 2y =40
  so by solving this we get x = 20.(ans)
• 11 years agoHelpfull: Yes(2) No(0)
• ans .= 20
  right sum= x, wrong sum = 30-x
  (3*x)- (30-x)*2 = 40
  x= 20
• 10 years agoHelpfull: Yes(1) No(0)
• Ans:2
  20*3=60
  10*2=20
  60-20=40 is obtained marks
  so ans is option 2
  
• 12 years agoHelpfull: Yes(0) No(1)
• right answers is 20.if put correct 20 questions they got 60 marks.total attempts is 30.so the wrong answers is 10.so they lost 20 marks.60-20=40
• 11 years agoHelpfull: Yes(0) No(1)
• 20 correct answer=60 marks.
  10 wrong answer=-20 marks
  so total=40 marks
  Ans=20
• 11 years agoHelpfull: Yes(0) No(2)
• No.of Questions attend 30
  So if he get he get marks as 40 means so
  20*3-10*2=40
  So answer is (2)20
• 11 years agoHelpfull: Yes(0) No(0)
• x + y = 30 & 3x - 2y =40
  so by solving this we get x = 20.(ans)
  
• 9 years agoHelpfull: Yes(0) No(0)
• 20 sums were attempted correctly...
  let a be correct ones and b be wrong ones
  total sums attempted are 30...
  a+b=30.
  3a-2b=40(given)
  solving both eq we get
  a=20
  b=10...
• 9 years agoHelpfull: Yes(0) No(0)
• 20
  20*3-10*2=40
  
• 9 years agoHelpfull: Yes(0) No(0)
• let number of correct questions be x
  let no of incorrect questions be y
  x+y=30
  now
  3 marks for correct question and -2 marks for incorrect questions.
  so
  3x-2y=40
  on solving we get
  x=20
• 6 years agoHelpfull: Yes(0) No(0)
• 20
  let x questions submitted correctly
  3*x-2(30-x)=40
  x=20
• 6 years agoHelpfull: Yes(0) No(0)
• 20 correct question
• 6 years agoHelpfull: Yes(0) No(0)