Given:
An arithmetic progression (A.P.):
\[
\frac{13}{3}, \frac{9}{3}, \frac{5}{3}, \dots
\]
We need to find the 15th term of this A.P.
Step 1: Identify the first term \(a\) and common difference \(d\)
First term:
\[
a = \frac{13}{3}
\]
Second term:
\[
a_2 = \frac{9}{3} = 3
\]
Calculate common difference \(d\):
\[
d = a_2 - a = 3 - \frac{13}{3} = \frac{9}{3} - \frac{13}{3} = -\frac{4}{3}
\]
Step 2: Use formula for \(n\)th term of an A.P.
The \(n\)th term \(a_n\) is given by:
\[
a_n = a + (n - 1)d
\]
Substitute \(n = 15\), \(a = \frac{13}{3}\), and \(d = -\frac{4}{3}\):
\[
a_{15} = \frac{13}{3} + (15 - 1) \times \left(-\frac{4}{3}\right) = \frac{13}{3} + 14 \times \left(-\frac{4}{3}\right)
\]
\[
= \frac{13}{3} - \frac{56}{3} = \frac{13 - 56}{3} = -\frac{43}{3}
\]
Final Answer:
\[
\boxed{-\frac{43}{3}}
\]