Multiple choice

The average marks of 45 students in a science exam is 64. Later it is found that three marks 68, 58 and 72 were wrongly written as 86,46 and 58.The average after mistake were rectified is. विज्ञान की परीक्षा में 45 छात्रों के औसत अंक 64 है। बाद में पता चलता है कि तीन अंक 68, 58 और 72 गलती से 86, 46 और 58 लिख लिए गये थे। गलतियां सुधारने के बाद औसत हैः

  1. 66

  2. 62

  3. 64.9

  4. 64.17

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Total marks = 45 × 64 = 2880. Wrong total = 86 + 46 + 58 = 190. Correct total = 68 + 58 + 72 = 198. Difference = 198 - 190 = 8. New average = (2880 + 8) / 45 = 2888/45 = 64.17.