The following table shows the marks of 90 students in a test of 80 marks :<br> <table> <thead><tr><th>Marks</th><th>Number of students</th></tr></thead> <tbody> <tr><td>1-10</td><td>5</td></tr> <tr><td>11-20</td><td>8</td></tr> <tr><td>21-30</td><td>10</td></tr> <tr><td>31-40</td><td>13</td></tr> <tr><td>41-50</td><td>18</td></tr> <tr><td>51-60</td><td>17</td></tr> <tr><td>61-70</td><td>12</td></tr> <tr><td>71-80</td><td>7</td></tr> </tbody> </table> <br>The percentage of students who have obtained <strong>LESS THAN OR EQUAL TO</strong> 50% marks is

  1. A. 30%
  2. B. 40%
  3. C. 45%
  4. D. 60%

Correct Answer: B. 40%

Explanation

50% of the maximum 80 marks is 40. The students scoring \leq 40 are in the first four class intervals. Number of students = 5 + 8 + 10 + 13 = 36. The percentage is \frac{36}{90} \times 100 = 40\%.

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