Sunday

September 21, 2014

September 21, 2014

Posted by **Abdela** on Thursday, February 16, 2012 at 6:54am.

Find the arthemetic progression?

- Math sequence -
**Reiny**, Thursday, February 16, 2012 at 8:43amso the sum of the first 9 terms would be 99

sum(5) = 30 ---> (5/2)(2a + 4d) = 30

5(2a+4d) = 60

2a + 4d = 12

a + 2d = 6

sum(9) = 99 ----> (9/2)(2a + 8d) = 99

2a + 8d = 22

a + 4d = 11

subtract them

2d = 5

d = 5/2 or 2.5

then a = 1

the arithmetic sequence is

1 , 3.5, 6, 8.5 , ...

- Math sequence -
**Abubakar1idr**, Thursday, February 16, 2012 at 2:26pmWhat is lhe sum of lhe first 12 terms of an A.p whose first term is 15 and common difference is 13.

**Answer this Question**

**Related Questions**

Maths - 1..The first 2 terms of a geometric progression are the same as the ...

Further mathematics - An exponential sequence (GP)of positive terms and a linear...

Further mathematics - An exponential sequence of positive terms and a linear ...

Math 12 - the sum of the first 2 terms of a geometric sequence is 3. the sum of...

Further mathematics - An exponential sequence of positive terms and a linear ...

Functions 11: Series and Sequence 2 - The sum of the first two terms of a ...

algebra 2 help please/check - The first 3 terms in a geometric sequence are 1.1...

Algebra II - The first 3 terms in a geometric sequence are 1.1, 1.65, and 2.475...

algebra 2 - The first 3 terms in a geometric sequence are 1.1, 1.65, and 2.475...

Math 12 - sum of 2nd and 5th terms of a geometric sequence is 13. the sum of ...