QUESTION

CSAT

Easy

Maths

Prelims 2015

In a test, a candidate attempted only 8 questions and secured 50% marks in each of the questions. If he obtained a total of 40% in the test and all questions in the test carried equal marks, how many questions were there in the test?

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Explanation

Let the total number of questions in the test be N. Each question carries equal marks, so the total marks in the test are proportional to N.

Given:

  • The candidate attempted 8 questions and secured 50% marks in each.
  • He obtained a total of 40% in the test.
  • All questions in the test carried equal marks.

Solution:

  1. Marks per question:
  • Let the total marks for the test be M.
  • Since all questions carry equal marks, each question is worth M/NM/N marks.
  1. Marks obtained by the candidate:
  • The candidate attempted 8 questions and secured 50% marks in each.
  • Therefore, the marks obtained in each attempted question are 0.5(M/N)=M/(2N)0.5 \cdot (M/N) = M/(2N).
  • Total marks obtained by the candidate = 8(M/(2N))=4M/N8 \cdot (M/(2N)) = 4M/N.
  1. Total marks obtained as a percentage:
  • The candidate obtained 40% of the total marks.
  • Therefore, 4M/N=0.4M4M/N = 0.4 \cdot M.
  1. Solving for N:
  • Simplifying the equation: 4M/N=0.4M4M/N = 0.4 \cdot M 4/N=0.44/N = 0.4 N=4/0.4=10N = 4/0.4 = 10.

Therefore, the total number of questions in the test is N=10N = 10.

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