If a sequence follows the rule an = 3n - 2, what is the sum of the first 20 terms?
To find the sum of the first 20 terms in this arithmetic sequence, we can use the formula for the sum of an arithmetic series:

Sum = (n * (a1 + an)) / 2

where n is the number of terms, a1 is the first term, and an is the nth term.

First, let's find the first term (a1) and the 20th term (a20):

a1 = 3(1) - 2 = 1
a20 = 3(20) - 2 = 58

Now, using the formula, we have:

Sum = (20 * (1 + 58)) / 2
    = (20 * 59) / 2
    = 1180 / 2
    = 590

So, the sum of the first 20 terms in this sequence is 590.