Find the sum of the following arithmetic sequences for the number of terms indicated.
| 1. | 10, 20, 30, 40, .. | to 15 terms |
| 2. | 7, 11, 15, 19, ... | to 20 terms |
| 3. | 14, 8, 2, -4, ... | to 10 terms |
| 4. | w, 2w + 3, 3w + 6, 4w + 9, ... | to 35 terms |
| 5. | 3.6, 5.7, 7.8, 9.9, .. | to 27 terms |
| 6. | -2, ..., -311 | for 104 terms |
| 7. | 200, ..., 25, 0 | for 9 terms |
Find a formula for the sum of the first n terms of the arithmetic sequences below:
| 8. | 15, 20, 25, 30, ... |
| 9. | 2, 5, 8, 11, ... |
| 10. | 5, 1, -3, -7, ... |
11. Find the sum of the first 100 terms of an arithmetic sequence with a first term of 20, a common difference of 4
12. An arithmetic sequence has a first term of 6.
The sum of the first 10 terms is 262.5
Find the common difference.
 . |
13. A politician estimates that the number of handshakes he does each day before an election is increasing by about 10 per day. On the first day of the election campaign he shakes the hands of 45 people. How many hands will he have shaken altogether by the time of the election 30 days later? |
14. The first term of an arithmetic sequence is 6 and the common difference is 4. How many terms must be added together until the sum of the terms is equal to 510?
