# Algebra 2

posted by .

What is the first term of a geometric series with a summation of 800, 4 terms and a common ratio of 3?

• Algebra 2 -

easy way:
800/40 = 20

so, 20,60,180,540

or,

a(1+r+r^2+r^3) = a(r^4-1)/(r-1) = a*80/2 = 40a

so, a = 800/40 = 20

• Algebra 2 -

Thank you, I think I understand how to work it out now! That helped me out so much!

## Similar Questions

1. ### math studies

An arithmetic series has a first term of -4 and a common difference of 1. A geometric series has a first term of 8 and a common ratio of 0.5. After how many terms does the sum of the arithmetic series exceed the sum of the geometric …
2. ### ALG 2

What is the lat term, in a series of 10 terms with a common ratio of 2, a first term (a1) if 1 and a summation of 1023
3. ### ALG 2

What is the first term of a geometic series with a summation of 800, 4 terms and a common ratio of 3?
4. ### Algebra 2

What is the first term of a geometric series with a summation of 800, 4 terms and a common ratio of 3?
5. ### Geometric Series (Algebra 2)

I need some assistance or a formula when trying to find the first term of geometric series please! I don't understand this!!!! What is the first term of a geometric series with a summation of 289, 5 terms and a common ratio of 1/2?
6. ### Maths

1..The first 2 terms of a geometric progression are the same as the first two terms of an arithmetic progression.The first term is 12 and is greater than the second term.The sum of the first 3 terms od the arithmetic progression is …
7. ### Math(arithmetic & Geometric Series)

1)The sum of 6 terms of an arithmetic series is 45, the sum of 12 terms is -8. Find the first term and the common difference?
8. ### arithmetic

1. The first and last term of an A.P are, a and l respectively, show that the sum of nth term from the beginning and nth term from the end is a + l. 2. If mth term of an A.P be 1/n and nth term be 1/m, then show that its mnth term …
9. ### math C2 sequences and series

The eight,fourth and second terms of an arithmetic progression form the first three terms of a geometric series. The arithmetic progression has first term A and common difference d, and the geometric progression has first term G and …
10. ### algebra, series

The sum of the first n terms of a series is 1-(3/4). Obtain an expression for the nth term of the series. Prove that the series is geometric, and state the values of the first term and the common ratio. Please show workings

More Similar Questions