Answer:
$ 22.5
Step-by-step explanation:
B(x) = 30.50 - 0.20x
Notice that x defines the number of prints.
For prints = x = 40
B(40) = 30.50 - 0.20(40)
B(40) = 30.50 - 8
B(40) = 22.5
Remaining amount is $22.5
B(x) is defined as at starting you had $30.50 then you kept on spending with a period of 20 cents(= 0.20 dollar). So 30.50 kept on decreasing by 0.20. Each time you spend, you give 0.20.
That's why the function is 30.50 - 0.20x.
Where x is the nunber of times you spend(buying prints)
