ex_02_4.py

#!/usr/bin/python
#AUTHOR: alexxa
#DATE: 23.12.2013
#SOURCE: Think Python: How to Think Like a Computer Scientist by Allen B. Downey
# http://www.greenteapress.com/thinkpython/html/index.html
#PURPOSE: Chapter 2. Variables, expressions and statements

# 1
# The volume of a sphere with radius r is 4
# 3pr3. What is the volume of a sphere with radius 5?
# Hint: 392.7 is wrong
r,pi = 5,3.14
V = (4/3)*pi*(r**3)
print('Volume of a sphere with radius 5 is equal to {0:.2f}'.format(V));

# 2
# Suppose the cover price of a book is $24.95, but bookstores get a 40% discount. 
# Shipping costs $3 for the first copy and 75 cents for each additional copy. 
# What is the total wholesale cost for 60 copies?
price = 24.95*0.6
ship_cost = 3
ship_cost_copy = 0.75
total_sum = price + ship_cost + (price + ship_cost_copy)*59
print('Total wholesale cost for 60 copies is {0:.2f}'.format(total_sum))

# 3
# If I leave my house at 6:52 am and run 1 mile at an easy pace 
# (8:15 per mile), then 3 miles at tempo (7:12 per mile) and 1 mile 
# at easy pace again, what time do I get home for breakfast?
start_time = (6*60 + 52)*60
easy_time = (8*60 + 15)*2
tempo_time = (7*60 + 12)*3

breakfast_hour = (start_time + easy_time + tempo_time)/(60*60)
breakfast_int_hour = int(breakfast_hour)

breakfast_minute  = (breakfast_hour - breakfast_int_hour)*60
breakfast_int_minute = int(breakfast_minute)

print('Breakfast is at {}.{}'.format(breakfast_int_hour,breakfast_int_minute))

#END