Multiple choice

The mean of 20 items is 47. Later it is found that the item 62 is wrongly written as 26. Find the correct mean. 20 मदों का औसत 47 है। बाद में पता चला कि एक मद को 62 के स्थान पर गलती से 26 लिख दिया गया। तद्नुसार सही औसत ज्ञात कीजिए।

  1. 49.9

  2. 47.7

  3. 48.8

  4. 46.6
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The incorrect mean (47) was calculated with 26 instead of 62. Total sum with error = 47 × 20 = 940. Correct sum = 940 - 26 + 62 = 976. Correct mean = 976/20 = 48.8. Alternatively: difference in value = 62 - 26 = 36, so difference in mean = 36/20 = 1.8. Correct mean = 47 + 1.8 = 48.8.

Keep practicing — related questions