Question:medium

In an A.P., if \(a = 8\) and \(a_{10} = -19\), then value of \(d\) is:

Updated On: Jan 13, 2026
  • \(3\)
  • \(-\frac{11}{9}\)
  • \(-\frac{27}{10}\)
  • \(-3\)
Show Solution

The Correct Option is D

Solution and Explanation

The formula for the \(n\)-th term of an arithmetic progression (A.P.) is:

\[ a_n = a + (n - 1)d \]

Where:

  • \(a_n\) represents the \(n\)-th term,
  • \(a\) is the first term,
  • \(d\) is the common difference.

Given information:

  • First term, \(a = 8\),
  • 10th term, \(a_{10} = -19\).
  • Objective: Find the common difference, \(d\).

Applying the formula for the 10th term with the given values:

\[ a_{10} = a + (10 - 1)d \implies -19 = 8 + 9d \]

Solving for \(d\):

\[ -19 - 8 = 9d \implies -27 = 9d \implies d = \frac{-27}{9} \implies d = -3 \]

The common difference is:

\(d = -3\)

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