1.   3/6:
2.   def
3.   abc__123.46  (2 blanks)
4.   False
5.   3 -10

6.  7.  8.  9 . 10. 11.
B   A   D   A   D   D

12. 13. 14. 15. 16. 17.
E   B   B   C   D   B

18. This is a possible solution: 

# Note an earlier version I posted added a "$" to the dollar amounts, whereas the
# problem didn't really call for that.  On tests don't do more than is asked.

def computeTip( ):
    cost  = float( input( "Meal cost: " ) )
    level = int( input( "Satisfaction Level: " ))
    if level == 1:
        tip = 0.20 * cost
    elif level == 2:
        tip = 0.15 * cost
    else:
        tip = 0.10 * cost
    print("Please pay:", format( cost + tip, ".2f"))

19. A possible answer:

def largest():
    x1 = float(input("Number1: "))
    x2 = float(input("Number2: "))
    x3 = float(input("Number3: "))
    if (x1 >= x2 and x1 >= x3):
        print("The largest is", x1)
    elif (x2 >= x1 and x2 >= x3):
        print("The largest is", x2)
    else:
        print("The largest is", x3)