Question

Find the 15th term of the geometric sequence 10, 20, 40, ...

Answer 1

Answer:

70,110160,220,290,370,460 i thinks

step by step explanation

first no they added 10 next they added 20 so they are increasing 10

Answer 2

Given,

A G.P 10, 20, 40.....

To Find,

The 15th term of the G.P.

Solution,

The formula for calculating the nth term of G.P is

aₙ = arⁿ⁻¹

where r is the common ratio and a is the first term.

In this case

a = 10 and d = 2

So,

a₁₅ = 10(2)¹⁵⁻¹

a₁₅ = 10(2)¹⁴

a₁₅ = 163840

Hence, the 15th term of the G.P is 163840.