Answer:
The second one is the best answer to your question
1/4
and 6/4 there we go here is your answer
For this case we have that the total minutes spent in yoga classes last week was 165.
Subtracting the 45 minutes of the Saturday day we have:

Those 120 minutes were distributed in the weekly yoga classes
where each lasted 30 minutes.

So, 4 week yoga classes were held
ANswer:
4 week yoga classes were held