Question
In a competitive examination containing 200 questions, 2
marks are awarded for every correct answer and 1 mark gets deducted for every wrong answer. If a student attempted all questions and obtained 97 marks, how many wrong answers must he have given?Solution
Let number of questions with right answers = x ∴ No. of questions with wrong answers = 200 –x ∴ Marks obtained for right answers = 2x ∴ Marks deducted for wrong answers = 200 -x ∴ 2x – (200-x) = 97 ⇒ 3x = 200 + 97 ⇒ 3x = 297 ∴ x= 99 ∴ No. of questions with wrong answers (200 – 99) = 101
- 16, 36, 128, 768, 6144, 61440 
- 1286, 1061, 865, 696, 560, 431, 331 
- 9 20 63 255 1285 7716 ...
- 16,22,30,45,52,66 
- 48, 73, 109, 154, 222, 303 
- 3 5 9 17 32 65 ...
- Find the wrong number in the given number series. 
 
 25, 36, 50, 68, 92, 120
- Find the wrong number in given number series. - 6490, 6377, 6294, 6211, 6138 
- Find the wrong number in the given number series, - 121, 130, 116, 139, 103, 148 
- Find the wrong number in the given number series. 
 
 7, 9, 16, 12, 25, 15, 36