Find S9, the sum of the geometric series to the 9th term, in which a3=3.645 and a8=15

The sum of the first nine terms of the sequence is 74.44.

Step-by-step explanation:

Geometric sequence concepts:

The nth term of a geometric sequence is given by the following equation.

In which r is the common ratio.

This can be expanded for the nth term in the following way:

In which is the first term.

Or even:

The sum of the first n terms of a geometric sequence is given by:

Finding the common ratio:

Finding the first term:

Sum of the first nine terms:

The sum of the first nine terms of the sequence is 74.44.

$27.5

step-by-step explanation:

$110.00 divided by 4

rick has $1400 and sally has $1500

step-by-step explanation:

to find amount of money rick has after 10 years :

principal = $1000 , time = 10 years , rate = 4% annually

to find amount of money sally has after 10 years :

her friend gives to pay her $50 per year, therefore money she has after 10 years = 50 × 10 = $500

also, sally gets $1000 after 10 years,

therefore, total amount of money sally has after 10 years = 500 + 1000 = $1500

so, after 10 years : rick has $1400 and sally has $1500