15-110 PS2 Sample Solutions - Spring 2018

1.
(a) 41 - 30 / 3 + 2
    41 - 10.0 + 2
    31.0 + 2
    33.0   (33 also accepted)
(b) 3 ** 2 ** 3
    3 ** 8
    6561
(c) 23456 % 1000 + 23456 % 1000
    456 + 23456 % 1000
    456 + 456
    912

2.
(a) Type error - can't add a boolean to a string
(b) Value error or domain error - can't take square root of a negative number
(c) Syntax error - can't use def as a variable name since it is a reserved word
(d) ZeroDivision error - modulo uses division and we can't divide by 0

3. 
(a) The answer is not correct since the units do not match (feet vs. yards).
(b) Python reports an error since the function requires 2 arguments and
    we only supplied one.
(c) Python does not report an error since Python can't tell the meaning
    of the two numbers so it looks valid.
(d) None (the function prints to the screen but does not return an
    answer to the instruction that called the function

4. 
(a) 729 (loop iterates 6 times) = 3**6
(b) 3**n
(c) 720 = 6!
(d) n!
(e) The function always returns 3. The return is part of the loop body. 
    During the first iteration, the return exits the function 
    immediately so the loop never completes.

5.
(a) Every image from camera, phone, etc. have embedded time and serial
    number data so if he registered the device, he can be traced.
    In the reading (on page 24), a case was described about a fan 
    posting pictures of a Harry Potter release online before it was 
    released officially.
(b) The EZPass records the time she entered and exited the freeway 
    as well as the distance traveled. Her average speed can be 
    computed which implied that she had to have been speeding 
    at some point along the way. (see page 37 in the reading)