What will be the Removed Number? If

The average of 6 numbers is 20. if one number is removed, the average becomes 15. What is the number removed?

  1. 5
  2. 35
  3. 112
  4. 45
Manish Listener Asked on 15th July 2015 in Maths.
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  • 1 Answer(s)

    Answer: (4). 45

    The average of 6 numbers is equal to 20.
    Average = Sum of the observation / No. of observation
    let sum of 6 observation be. X
    Therefore, 20 = X / 6
                             X = 120 . hence, sum of 6 observation is 120.

    Now, we have to find the number which is removed from these 6 observations, and forms new average be 15.
    let the removing number be Y.
    so, the number of observations after removing one number is 5, and the new sum of observations is 120 – Y.
    As, we know that the formula for finding average so,
     15 = 120 – Y/ 5
      75 = 120 – Y
      Y = 120 – 75
      Y = 45.
    Hence, the no. which is removed 45.

    vijay Professor Answered on 15th July 2015.
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