A student attempts x number of questions. He answers 15 correctly out of first 20 questions and of the remaining questions, he answers 1/3 correctly. If all questions have same credit and the student gets 50 % marks, then find the value of x.
Student attempts x questions.
2) Out of 20 questions he answers 15 correctly and of (x – 20) questions he answered 1/3 correctly.
3) The student gets 50 % marks.
Therefore,
15 +
1
(x – 20) = 50% of x
3
15 +
1
(x – 20) =
50
× x
3
100
15 +
1
(x – 20) =
x
3
2
90+2 (x-20)=3x
Solving this equation, we get
x=50 Hence, the number of question attempted by the students = 50
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