More Questions from Average

The average of the sequence 100, 200, 300, ..., 1000 is 550. If each term is divided by 5, what is the new average?

Aptitude Average Difficulty: Easy
Choose an option
  • A
    450
  • B
    45
  • C
    55
  • D
    None of these
  • E
    110

Answer

Correct Answer: None of these

Explanation

Introduction / Context:Transformations applied uniformly to every term in a data set apply the same transformation to the average. This property lets us compute new averages quickly without re-summing all terms.

Given Data / Assumptions:

  • Original sequence: 100, 200, 300, ..., 1000 (step 100)
  • Original average = 550
  • Operation: divide each term by 5

Concept / Approach:If each data point is divided by a constant k, the average is also divided by k. Thus New average = Old average / 5.

Step-by-Step Solution:

Old average = 550 New average = 550 / 5 = 110

Verification / Alternative check:New sequence becomes 20, 40, 60, ..., 200. The first and last terms’ mean is (20 + 200) / 2 = 110, matching the transformation rule.

Why Other Options Are Wrong:

  • 450: Incorrect scaling; seems like subtracting 100 instead of dividing.
  • 45 and 55: Both reflect order-of-magnitude mistakes.
  • None of these: Correct, since the true new average 110 is not listed among the numeric options.

Common Pitfalls:Confusing division with subtraction, or mistakenly dividing by the number of terms again after transformation.

Final Answer:None of these (the correct new average is 110).

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