The sequence is 5, 10, 20, 40

Answer: Geometric Progression with first term a=5a = 5, common ratio r=2r = 2, and general term an=5⋅2n−1a_n = 5 \cdot 2^{n-1}.

Step-by-step solution

Step 1: Check the ratio between consecutive terms

To determine the nature of the sequence, we compute the ratio between each term and the term preceding it. Since the ratio is constantly equal to 22, the sequence is a Geometric Progression (GP) with common ratio r=2r = 2.

Step 2: Identify the first term and general formula

The first term of the geometric progression is a=5a = 5, and the common ratio is r=2r = 2. The standard formula for the nthn^{\text{th}} term of any geometric progression is given by an=arn−1a_n = a r^{n-1}.

Step 3: Substitute values to find the nth term

Substituting a=5a = 5 and r=2r = 2 into the general formula gives the nthn^{\text{th}} term as an=5⋅2n−1a_n = 5 \cdot 2^{n-1}. For instance, the next term (5th5^{\text{th}} term) is 5⋅24=5⋅16=805 \cdot 2^{4} = 5 \cdot 16 = 80.

Solve your own maths question free →