Write the corresponding arithmetic series described in each of the following and find its sum.

1. sum of the first 10 positive even integers

2. sum of all two-digit multiples of 11

3. sum of the first 30 positive integers which are multiples of 8

4. sum of all the numbers between 8 and 45 that are divisible by 6

5. sum of the first 8 terms of the arithmetic sequence 8, 15, 22, 29, ...​