Multiple choice

Which term of the sequence $-7, -2, 3, 8,.........$ is $73$?

  1. $17$
  2. $18$
  3. $16$

  4. none
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A Correct answer
Explanation

This is an arithmetic progression with first term a = -7 and common difference d = 5. The nth term is a + (n-1)d = 73. So -7 + (n-1)5 = 73, which simplifies to 5(n-1) = 80, so n-1 = 16, n = 17.

AI explanation

The sequence has a constant common difference of 5, so it is an arithmetic progression. Using the nth term formula, a + (n - 1)d = 73, we substitute the first term a = -7 and d = 5 to get -7 + (n - 1)5 = 73. Solving this gives 5(n - 1) = 80, so n - 1 = 16 and n = 17.

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