A long session lasts 50 minutes.
Step-by-step explanation:
Let,
Duration of long session = x
Duration of short session = y
According to given statement;
3x+4y=270 Eqn 1
each long session lasts twenty minutes longer than the short session.
x = y + 20 Eqn 2
Putting value of x from Eqn 2 in Eqn 1
Dividing both sides by 7
Putting y = 30 in Eqn 2
A long session lasts 50 minutes.
Keywords: linear equation, substitution method
Learn more about substitution method at:
#LearnwithBrainly