print("welcome to the bill calculator")
minutes = float(input("number of minutes you used: "))
data = float(input("the amount of data you used in GB: "))
print("your basic plan costs $39.99 per month")
mcost = (minutes - 450) * .45
print("you will be charged " + str(mcost) + " for the minutes you used")
print("the monthly data fee is $30.00")
dcost = (data - 3) * 10
print("you will be charged " + str(dcost) + " for the extra data you used")
total = mcost + dcost + 69.99
print("your total bill is " + str(total))
the 20 value your teacher gave may be incorrect, bc 4.2-3*10 = 12 not 20, making the total 109.89
