Answer:
4 sessions.
Step-by-step explanation:
He starts with 10 minutes practiced and has to finish his quota in 20 minute sessions, so we can represent that with the equation 90=20x+10. Then solve for x.
90=20x+10
Subtract 10
80=20x
Divide by 20
x=4
It would take 4 sessions.
Answer:
1 10 min session + x 20 min sessions = 90 min
10+20x=90
20x=80
x=4 sessions