Question

Difficulty: EasyArithmetic and Geometric Progressions (AP and GP)

The first term of a geometric progression (GP) is 22 and its common ratio is 33. What is the 4th4^{\text{th}} term of the progression?

  1. 5454Answer
  2. B
    162162
  3. C
    1111
  4. D
    2424

Answer

The 4th4^{\text{th}} term of the geometric progression is 5454.
For a geometric progression with first term aa and common ratio rr, the nthn^{\text{th}} term is given by Tn=arn1T_n = a r^{n-1}. Substituting a=2a = 2, r=3r = 3, and n=4n = 4 yields T4=2×33=2×27=54T_4 = 2 \times 3^3 = 2 \times 27 = 54.

Step-by-Step Solution

1
Identify the given parameters of the geometric progression.
First term a=2a = 2, common ratio r=3r = 3, and term position n=4n = 4.
These values are directly provided in the question statement.
2
Apply the general formula for the nthn^{\text{th}} term of a geometric progression, Tn=arn1T_n = a r^{n-1}.
T4=2×341=2×33T_4 = 2 \times 3^{4-1} = 2 \times 3^3.
The exponent of the common ratio is always one less than the term index nn.
3
Evaluate the exponent and multiply by the first term.
33=273^3 = 27, so T4=2×27=54T_4 = 2 \times 27 = 54.
Performing standard arithmetic yields the exact term value.

Key Concept

Formula for the nth term of a Geometric Progression: Tn=arn1T_n = a r^{n-1}
Estimated Time:45s
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