Ch. 3

Question 1

the value 4! is

Answer 1

factorial of 4, 4 × 3 × 2 × 1 = 24.

Question 2

4.0 / 10.0 + 3.5 * 2

Answer 2

1. • and / from left to right.
2. • and - from left to right.
     a) first divide 4.0 and 10.0, which equals 0.4
     0.4 + 3.5 * 2
     b) multiply 3.5 and 2, which equals 7.0
     0.4 + 7.0
     c) add, equation equals 7.4

Question 3

10 % 4 + 6 / 2

Answer 3

1. modulo %
2. / and + from left to right
   a) 10 % 4 equals 2 because % calculates remainder
   2 + 6 / 2
   b) divide 6 / 2, equals 3
   2 + 3
   c) add, equation equals 5

Question 4

abs (4 - 20 // 3) ** 3

Answer 4

1. integer division //
2. • from left to right
3. absolute value, abs()
4. exponent **
   a) 20 // 3 equals 6 because // 20 divided by 3 is 6.6667, so round down to get 6
   abs(4 - 6) ** 3
   b) subtract 4 and 6, equals -2
   abs(-2) ** 3
   c) abs makes neg to pos, abs(-2) equals 2
   2 ** 3
   d) 2 ** 3 equals 8 because 2 * 2 * 2 = 8

Question 5

sqrt(4.5 - 5.0) + 7 * 3

Answer 5

1. subtract 4.5 and 5.0, equals -0.5
   sqrt(-0.5) + 7 * 3
2. multipy 7 and 3
   sqrt(-0.5) + 21
3. sqrt(-0.5) equals error?

Question 6

3 * 10 // 3 + 10 % 3

Answer 6

1. multiply first
   30 // 3 + 10 % 3
2. divide
   10 + 10 % 3
3. modulo, remainder of 10 divided by 3 is 1
   10 + 1
4. add
   11

Question 7

3 ** 3

Answer 7

1. 3 *3 = 9
2. 9 * 3= 27

Question 8

(3 + 5)(5)

Answer 8

(3 + 5) * 5

Question 9

n(n - 1)/2

Answer 9

n * (n -1) / 2

Question 10

range(5)

Answer 10

0,1,2,3,4

Question 11

range(3, 10)

Answer 11

3,4,5,6,7,8,9

Question 12

range(4, 13, 3)

Answer 12

4,7,10
start at 4, with increment of 3, and stop but not include 13

Question 13

range(15, 5, -2)

Answer 13

15,13,11,9,7
start at 15, with increment of -2, and stop but not include 5

Question 14

range(5,3)

Answer 14

error bc 5 is greater than 3

Question 15

for i in range(1,11):
print (i*i)

Answer 15

range is 1,2,3,4,5,6,7,8,9,10
1
4
9
16
25
36
49
64
81
100

Question 16

for i in [1,3,5,7,9]:
print(i, “:”, i**3)
print(i)

Answer 16

1:1
3:27
5:125
7:343
9:729
9

Question 17

x=2
y=10
for j in range(0,y,x):
print(j, end=” “)
print(x+y)
print(“done)

Answer 17

0 12
2 12
4 12
6 12
8 12
done

Question 18

ans=0
for i in range(1,11):
ans = ans + i*i
print(i)
print(ans)

Answer 18

1
2
3
4
5
6
7
8
9
10
385

Question 19

what do you think will happen if you use a negative number in the second parameter of the round function?
Ex: print(round(314.159265, -1))

Answer 19

neg in second parameter is to round to the nearest 10, 100, 1000, etc. -1 means to round to the nearest 10th place.
output: 310
if it were -2, output would’ve been 300

Question 20

-10 // 3

Answer 20

1. -10 // 3 equals to -3.3333
2. round to lower number
   output: -4

Question 21

-10 % 3

Answer 21

1. a % b = a - (a // b) * b
   -10 - (10 // 3) * 3
2. -10 - (-4) * 3
3. -10 - (-12)
4. -10 + 12
5. output is 2

Question 22

10 // -3

Answer 22

1. 10 // -3 equals to -3.3333
2. round to lower number
   output: -4

Question 23

10 % -3

Answer 23

1. a % b = a - (a // b) * b
   10 - (10 // -3) * -3
2. 10 - (-4) * -3
3. 10 - (12)
4. 10 - 12
5. output is -2

Question 24

-10 // -3

Answer 24

1. -10 divided by -3 is 3.333
2. round to lowest int
   outcome: -4

Question 25

write a program to calculates the volume and surface area of a sphere from its radius, given as input. use given formula of volume and surface area

Answer 25

radius = float(input(“Enter the radius of the sphere: “))

pi = 3.14
volume = (4/3) * pi * radius ** 3
surface_area = 4 * pi * radius ** 2

print(“Volume of the sphere:”, volume)
print(“Surface area of the sphere:”, surface_area)

Question 26

write program that calculates the cost per square inch of a circular pizza, given its diameter and price. use formula for area

Answer 26

diameter=float(input(“enter the diameter of pizza:”))

pi = 3.14
sq_in = pi * (diameter / 2) **2

cost_per_in = sq_in * 0.60
print (“cost per square inch of pizza is”, cost_per_in)

Question 27

write a program that calculates the molecular weight of a carbohydrate. the program should prompt the user to enter the number to hydrogen atoms, the number of carbons atoms, and number of oxygen atoms. the program then prints the total combined molecular weight of all the atoms based on these individuals atom weight. weight of H = 1.00794; C = 12.0107; O = 15.9994

Answer 27

num_h = float(input(“enter number of hydrogen molecules: “))
num_c = float(input(“enter number of carbon molecules: “))
num_o = float(input(“enter number of oxygen molecules: “))

weight = (1.00794 * num_h) + (12.0107 * num_c) + (15.9994 * num_o)

print(“weight of carbohydrate molecule is”, weight)

Question 28

write a program that determines the distance to a lightning strike based on the time elapsed between the flash and the sound of thunder. the speed of sound is approximately 1100 ft/sec and 1 miles is 5280 ft.

Answer 28

time = float(input(“enter time elapsed between flash and thunder: “))

spe_sou = 1100 * time
dist = 5280 / spe_sou

print(“distance of lightning is”, dist, “ miles”)

Question 29

a coffee shop is selling coffee at $10.50 a pound plus the cost of shipping. each order ships for $0.86 per pound + $1.50 fixed cost for overhead. write a program that calculates the cost of an order

Answer 29

lbs = float(input(“enter pound of coffee”))

cof= (10.50 * lbs) + (.86 * lbs) + 1.50

print(“cost of coffee is”, cof)

Question 30

write a program to find the sum of the cubes of the first n natural numbers where the value of n is provided by the user

Answer 30

total = 0
n = int(input(“enter number: “))
for i in range(1, n + 1):
total += i ** 3
print(total)