Answer:
40 shows
Step-by-step explanation:
Seth’s father has spent $140.
At the regular price, the number (n) of shows Seth could attend is
n = 140/3.50
n = 40
If Seth attends 40 shows at that price, he will have spent $140.
Every show after that will cost only $1 instead of $3.50.
Seth must attend 40 shows for it to benefit his father.