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Averages · Question 4 of 62

Question 4

EasyOriginal question

What is the average of the first 20 odd natural numbers?

Options for question 4

Show the answer and explanation
CorrectNot quiteAnswer A

Correct answer: A

Explanation

  1. The first 20 odd numbers are 1, 3, …, 39.

  2. Average = 1+392=20\frac{1 + 39}{2} = 20.

Worth noting

Shortcut: the first n odd numbers add up to n², so their average is n. 400 is the sum; 39 is the last term.

Concept
Average of the first n odd numbers is n
Typical time
30 s
Your time
—
The rule this testsSimple average
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Ten questions from Averages, at your own pace.

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