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
What will come in place of the question mark (?) in the following series?
75, 219, 388, ?, 809, 106516.12 × 15.94 + 654.92 – 344.83 = ?× 5.95
660, 653, 639, 618, 590, ?
120, 126, 138, 162, ?, 306
11          20          ?             64          112        192
...Find the missing term in the series:
2, 5, 11, 23, 47, ?
580 557 528 497 ? 419
17, 38, 123, 508, ?, 15426
What will come in place of the question mark (?) in the following series?
55, 176, 320, ?, 685, 910
161Â Â Â Â 173Â Â Â Â Â Â 191 Â Â Â Â Â Â 215Â Â Â Â Â Â 245 Â Â Â Â Â Â ?
...
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