Maths · Arithmetic and Geometric progressions

Find the number of terms of the AP

Find the number of terms of the AP \( 121,117,113, \dots,-3 ? \)

  • A. 32
  • B. 30
  • C. 28
  • D. 26

Step-by-step solution

Given AP: 121, 117, 113, ..., -3. First term a = 121, common difference d = -4, last term l = -3. Using nth term formula l = a + (n-1)d, we get -3 = 121 + (n-1)(-4). Solving: -124 = -4(n-1) → n-1 = 31 → n = 32. Thus, there are 32 terms.
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