The first three terms of an arithmetic sequence are 1, 10 and 19, respectively. What is the value of the 27th term?
The common difference of an arithmetic sequence is the difference of any two consecutive numbers. The nth term of a sequence, in this case the 27th term, is equal to, (the common difference multiplied by n-1) + the first number in the sequence. Since the common difference in this arithmetic sequence is 10-1=9 or 19-10 = 9, and the first term in the sequence is 1, the 27th term will be 9*(27-1) + 1 = 9*26+1 = 235 :)