Answer:
120 ≤ 20c + 40s
Step-by-step explanation:
(Assuming her name is Kylie, who is giving 40 minute science sessions and 20 minute Chinese sessions.)
The unit for time will be minutes.
Write an equation for time needed for science sessions
40s = t
Write an equation for time needed for Chinese sessions
20c = t
Combine the two equations for the total time.
20c + 40s = total time
She does not want the total time to be more than two hours.
Convert two hours to minutes. There are 60 minutes in an hour.
2h * 60mins = 120 mins
Therefore t ≤ 120. Include this into the equation.
120 ≤ 20c + 40s