Sums of arithmetic progressions

[doreent0722]

1). Find the fourth term of the sequence of partial sums for the given sequence.
{5+ 3\2 n}

2). A bicycle rider coasts downhill, traveling 7 feet the first second. In each succeeding second, the rider travels 6 feet farther than in the preceding second. If the rider reaches the bottom of the hill in 9 seconds, find the total distance traveled.

S=________ feet

 

[MarkFL]

We ask that you post no more than two questions in the initial post of a thread. I have split your latest 4 questions into two threads.

We also ask that you give your thread a title that briefly describes the questions being asked. I have retitled your threads.

And we also ask that when you post questions, you show what you have tried, so we know where you are stuck. Can you show what you've tried for these problems?