Final answer:
The nth term of the sequence is calculated using the arithmetic sequence formula an = a1 + (n-1)d. With a1 = 20 and the common difference d = -0.2, the nth term expression is 20.2 - 0.2n.
Step-by-step explanation:
To find the nth term of the given sequence b, 20, 19.8, 19.6, 19.4, we first need to determine the pattern or the rule that the sequence follows. We can observe that from the second term onwards, each term is decreasing by 0.2 from the previous term. This is a linear sequence, and we can express this pattern with the formula for the nth term of an arithmetic sequence, which is an = a1 + (n-1)d, where an is the nth term, a1 is the first term of the sequence, and d is the common difference.
Since the first term we are given is 20, and the common difference d is -0.2, we substitute these values into the formula to get the expression for the nth term:
an = 20 + (n-1)(-0.2) = 20 - 0.2n + 0.2 = 20.2 - 0.2n
So the nth term of the given sequence is 20.2 - 0.2n.