Answer:
18 more sessions
Explanation:
Her goal is to practice 800 minutes.
She already did 175 minutes.
That means she has 800 - 175 = 625 minutes remaining, and she says that she will only practice in 35 minute sessions.
To determine the number of sessions she has left, just divide 625 by 35.

= 17.85714
However, you can't have a portion of a session, as she only does 35 mins every session. Therfore, she must do 18 more sessions.
I hope this helped!
~~~Harsha~~~