Find the twenty-fifth term of the arithmetic progression if a1 = 17.6 and. d = -0.4.

To find the twenty-fifth term a25 of this arithmetic sequence, we use the formula for the nth term of the arithmetic progression an = a1 + (n – 1) * d for n = 25, where a1 is the first term of the arithmetic progression, d is the difference of the arithmetic progression.

According to the condition of the problem, in this progression a1 = 17.6 and d = -0.4, therefore, we can write:

a25 = a1 + (25 – 1) * d = a1 + 24 * d = 17.6 + 24 * (0.4) = 17.6 – 24 * 0.4 = 17.6 – 9.6 = 8.

Answer: The 25th term of this arithmetic progression is 8.