Posted by **lYDIA** on Sunday, January 16, 2011 at 12:06am.

In an arithmetic sequence, the first term is 100 and the sixth term is 85. Find the common difference. Then, find the 50th term of the sequence.

Do I use the formula an=a1+(n-1)d?

If so, what would my "n" by in the equation?

- MATH -
**tchrwill**, Sunday, January 16, 2011 at 9:28am
The nth term of an arithmetic progression is defined by N = a + (n-1)d where N = the nth term, a = the first term and d = the common difference.

Therefore,

85 = 100 + (6 - 1)d

-15 = 5d making d = -3

The 50th term then becomes

N(50) = 85 + (50 - 1)(-3) = ?

- MATH -
**Bri**, Sunday, January 23, 2011 at 4:38pm
-402

- MATH -
**la**, Friday, January 28, 2011 at 3:45pm
ah what!!!!!!!!!!!!!!!!!!!

## Answer this Question

## Related Questions

- Algebra - True or False 1. – 5, – 5, – 5, – 5, – 5, … is an arithmetic sequence...
- Math - A sequence is formed by adding together the corresponding terms of a ...
- Arithmetic Sequence - Given the third term of an arithmetic sequence less than ...
- math - find the rule for the Nth term of the arithmetic sequence. 11/2, 25/6, 17...
- Sequence - Find the common difference and a formula formula for the nth term of ...
- Mathematics : Arithmetic Sequence - The 5th term and the 8th term of an ...
- math - The 3rd term in an arithmetic sequence is 12, the 7th term is 24, a) How...
- arithmetic sequence - the 40th term of an arithmetic sequence is equal to the ...
- mathematics - 1.1 the third term of an arithmetic sequence is 8 and the 15 term ...
- Math ( Can You check my Work?) - 1.an = 3n - 1 2. an = 2(2n - 3) 3.an = 4^n 4.an...

More Related Questions