Multiple choice

The first three terms of a sequence are 3, 7 and 11. Find the 20th term of the sequence.

  1. 69

  2. 70

  3. 79

  4. 80
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C Correct answer
Explanation

This is an arithmetic progression with first term a=3 and common difference d=4. The n-th term is a + (n-1)d. For n=20, term = 3 + (19 * 4) = 3 + 76 = 79.

AI explanation

The sequence follows an arithmetic progression with a first term of 3 and a common difference of 4. The formula for the nth term is a + (n - 1)d, so the 20th term is 3 + (20 - 1)4. This simplifies to 3 + 19(4), which equals 3 + 76 = 79.

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