Community Pool offers 3 sessions on Saturday morning. Each is 35 mins with 10 mins between session. The last one ends at 11:05. When does the first one begin?

Question

It is a checkpoint on knowledge and I am having trouble figuring out how to phrase my answer. 

Answer 1

 

last session start at : 11: 05 - 435 =10: 30

 

Each session takes 10 minutes in between

 

second session end at 10: 30 - 10 =10:20

 

second session start at 10: 20-35 = 9:45

 

first session ends at 9:45 -10 =9:35

first session start at  9:35-35 = 9