Draw a venn diagram and shade P(A U B)
Shade both circles including intersection
Probability red, then blue
3/4 * 1/4 = 3/16
3/16 or 0.1875
You want to design a 30-minute workout. For the first 15 minutes, you will choose an aerobic exercise from running, kickboxing, or circuit training. For the second 15 minutes, you will work on strengths and/or balance choosing from weight training, TRX, Bosu, resistance bands or your core routine. How many such workouts are possible?
3*5 = 15 workouts
Determine if the events are independent or dependent.
You pick out a sock from your drawer, put it on and grab another sock from the drawer
Dependent
A bag contains 10 red marbles, 8 blue marbles and 2 yellow marbles. Find the theoretical probability of getting a blue marble.
8/20 = 2/5 = 0.4 or 40%
P(Internet)
9 + 26 = 35
35/50 = 0.70
Probability of picking blue, then green.
1/5 * 4/5 = 4/25
4/25 or 0.16
7 * 4 * 8 * 3 = 672 outfits
Determine if the events are independent or dependent.
You roll two number cubes and get doubles.
Independent
What is the theoretical probability of selecting a queen from a standard deck of cards?
4/52 = 1/13 = 0.077
Draw a Venn diagram to describe the following.
Suppose that 530 students play soccer, 290 students play basketball, and 130 students play both sports. There are a total of 1500 students at the school.
Just soccer - 400
Intersection - 130
Just basketball - 160
Neither sport - 810
Find the probability of being on time to both classes.
0.7 * 0.7 = 0.49
How many ways can the letters of the word TRIANGLE be arranged?
8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 = 40,320 ways
Use the definition of independence to determine if the events are independent.
P(A) = 3/10
P(B) = 5/10
P(A and B) = 3/20
3/10 * 5/10 = 0.15
3/20 = 0.15
Independent events
What is the probability of selecting a king or queen from a standard deck of cards, putting it back, and selecting another king or queen?
8/52 * 8/52
2/13 * 2/13
4/169 = 0.0237
P(Cats)
10 + 10 + 6 + 2 = 28
28 + 9 + 2 + 1 = 40
28/40 = 0.7 or 70%
Probability of throwing a strike.
0.7 * 0.6 + 0.3 * 0.2
0.42 + 0.06
0.48
How many license plates, consisting of 2 letters followed by 4 digits, are possible if we do not want to repeat any letters or numbers?
26 * 25 * 10 * 9 * 8 * 7
= 3,276,000 plates possible
Use the definition of independence to PROVE the events are independent. (show the math)
P(heads)
P(rolling a 6 on a cube)
P(heads) = 1/2
P(rolling a 6 on a cube) = 1/6
P(heads and 6)= 1/12
1/2 * 1/6 = 1/12
What is the probability of selecting an ace from a standard deck of cards, putting it aside, and selecting another ace?
4/52 * 3/51
12/2652
1/221 = 0.0045
In a survey of university students, 64 had taken mathematics course, 94 had taken chemistry course, 58 had taken physics course, 28 had taken mathematics and physics, 26 had taken mathematics and chemistry, 22 had taken chemistry and physics course, and 14 had taken all the three courses. Find how many take only math.
(Create a three way Venn diagram)
64 - 14 - 14 - 12 = 24 students
P(Win at least one match)
Win both: 0.7 * 0.8 = 0.56
Win, then lose: 0.7 * 0.2 = 0.14
Lose, then win: 0.3 * 0.5 = 0.15
0.56 + 0.14 + 0.15 = 0.85 or 85%
A phone number in the area consists of 10 digits. The first three digits are the area code 301. The next 7 digits are selected at random. How many combinations are possible if we do not reuse 3, 0 or 1?
7 * 7 * 7 * 7 * 7 * 7 * 7 = 823, 543 combinations
Use the definition of independence to test if the events are independent.
P(A) = 2/5
P(B) = 1/3
P(A and B) = 1/4
2/5 * 1/3 = 2/15
2/15 does not equal 1/4
Not independent
What is the theoretical probability that two random people share the same birthday (month and day)?
1/365
(technically 1/365.25)