Multiple choice

Find the 9th term of the given sequence: 1, 3, 6, 10.....

  1. 44

  2. 45

  3. 46

  4. 47
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B Correct answer
Explanation

The sequence is 1, 3, 6, 10, which are triangular numbers. The n-th term is n(n+1)/2. For n=9, the term is 9(10)/2 = 45.

AI explanation

The differences between consecutive terms are 2, 3, and 4, meaning this sequence follows the pattern of triangular numbers where the nth term equals n(n+1)/2. To find the 9th term, apply the formula to get 9(9+1)/2. This simplifies to 90/2, which gives the result 45.

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