To determine the total cost of attending [tex]\( y \)[/tex] yoga sessions, we need to consider the cost structure.
1. Cost of a yoga class per session: Each yoga session costs [tex]\( \$15 \)[/tex].
2. Mat fee per session: A mat fee of [tex]\( \$2 \)[/tex] is charged per session.
For each session, the total cost is the sum of the cost of the class and the mat fee:
[tex]\[
\text{Total cost per session} = 15 + 2 = 17
\][/tex]
To find the total cost for [tex]\( y \)[/tex] sessions, we multiply the total cost per session by the number of sessions [tex]\( y \)[/tex]:
[tex]\[
\text{Total cost for} \, y \, \text{sessions} = 17 \times y
\][/tex]
Thus, the expression representing the total cost for [tex]\( y \)[/tex] sessions is:
[tex]\[
17 y
\][/tex]
Therefore, the correct answer is:
[tex]\[
\boxed{17 y}
\][/tex]