Multiple choice

The average of 20 numbers is calculated as 35. It is discovered later that while calculating the average, one number, namely 85, was read as 45. The correct average is

  1. $36.5$
  2. $37$
  3. $37.5$
  4. $36$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Calculated total = 20 × 35 = 700 (using 45 instead of 85). Correct total = 700 - 45 + 85 = 740. Correct average = 740 ÷ 20 = 37. Difference of 40 distributed over 20 numbers adds 2 to the average.

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