In a competitive examination,

Question:

In a competitive examination, 1 mark is awarded for each correct answer while 1/2 mark is deducted for every wrong answer. Jayanti answered 120

questions and got 90 marks. How many questions did she answer correctly?

Solution:

Let x be the number of correct answers of the questions in a competitive examination, then (120 – x) be the number of wrong answers of the

questions.

Then, by given condition,

$x \times 1-(120-x) \times \frac{1}{2}=90$

$\Rightarrow$ $x-60+\frac{x}{2}=90$

$\Rightarrow$ $\frac{3 x}{2}=150$

$\therefore$ $x=\frac{150 \times 2}{3}=50 \times 2=100$

Hence, Jayanti answered correctly 100 questions.

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