Hi

3+9+15+21+...+57 

arithmetic series, d= 6



   57 = 3 + (n-1)6

   60 = 6n

    n = 10, 57 is the 10th term





 

RELATED QUESTIONS

Find the sum of the following arithmetic series 
5+9+13+17+......41
The sum of this... (answered by Big Poop)

Can someone please help me?
1. Find the sum of each arithmetic series.
Part I: -15 + -3  (answered by josgarithmetic)

Find the sum of the first eight terms of the arithmetic series 3 + 5 + 7 + 9... (answered by josgarithmetic)

A partial sum of the arithmetic series is given. Find the sum:  3 + 5 + 7 + . . . +... (answered by ewatrrr)

Find the sum of 15 terms of an arithmetic series if the middle term is 92  (answered by greenestamps)

Find the sum of 15 terms of an arithmetic series if the middle term is... (answered by MathLover1)

What is the sum of the finite arithmetic... (answered by ewatrrr)

find the number of terms and the sum of each of the following arithmetic series.... (answered by fractalier)

Find the sum of the first 20 terms in the arithmetic series 15 + 4 - 7 - ...
 (answered by ikleyn)