# Math

the sum of the first n terms of an arithmetic series is -51. the series has a constant difference of -1.5 and a first term of four. Find the number of terms in the sum

I find using an EXCEL spreadsheet is very helpful for these types of problems. Start with 4 and keep adding 1.5. Then sum the series ending at each of the values. I get n=12

1. 👍 0
2. 👎 0
3. 👁 136

## Similar Questions

1. ### math

The sum of the 1st nine terms of an arithmetic series is 216. The 1st,3rd and the 7th terms of series form the 1st three terms of a geometric series. Find the 1st term and the constant difference of the arithmetic series ?

asked by mpho makua on August 14, 2016
2. ### Math

Consider the following series: 1,2,3,4,5,10,20,40....which starts as an arithmetic series? ...but after the first five terms becomes a geometric series. Prove that any positive integer can be written as a sum of distinct numbers

asked by MO on May 17, 2016
3. ### arithmetic

In an arithmetic series, the terms of the series are equally spread out. For example, in 1 + 5 + 9 + 13 + 17, consecutive terms are 4 apart. If the first term in an arithmetic series is 3, the last term is 136, and the sum is

asked by Cennie on September 24, 2010
4. ### Algebra

In an arithmetic series, the terms of the series are equally spread out. For example, in 1 + 5 + 9 + 13 + 17, consecutive terms are 4 apart. If the first term in an arithmetic series is 3,the last term is 136, and the sum is

asked by Daniel on July 14, 2009
5. ### Math

An arithmetic series has first term -50 and common difference 4. How many terms are in the series so that the sum of the series first exceeds 100?

asked by Lucas on November 24, 2017
6. ### Induction

Given the series 1,2,3,4,5,10,20,40,80,..... which starts as an arithmetic series for the first five terms and then follows geometric series. It can be proved by strong induction that any positive integer can be written as a sum

asked by bcruga on September 28, 2017
7. ### 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

asked by ll on September 28, 2008
8. ### Math question

In an arithmetic series, the 15th term is 43 and the sum of the first 15 terms is 120. Add the first 20 terms of the series.

asked by Anonymous on June 2, 2013
9. ### Algebra

If the first and the last terms of an arithmetic series are 10 and 62, show that the sum of the series varies directly as the number of terms

asked by Anonymous on February 7, 2017
10. ### math

The sum of the first 9 terms of an arithmetic series is 144, and the sum of the first 14 terms is 329. Find the first 4 terms of the series.

asked by Peter on January 23, 2017

More Similar Questions