Basic Probability
what is the probability of flipping heads on a fair coin?
1/2
flipping a coin and rolling a die. Are these events independent?
yes
You have 3 green and 1 red marble. If you pick one and don't replace it, what is the probability that the first is green and the second red?
(3/4) x (1/3)= 3/12=1/4
what does probability represent?
chance of an event happening.
What's the chance tomorrow's weather forecast could change?
not certain/probability is never 100%
A bag has 3 red marbles and 1 blue. What's the probability of picking red?
3/4
What is the probability of flipping heads and rolling a 3?
1/2 x 1/6= 1/12
A bag has 5 red and 5 blue marbles. You pick two marbles without replacing. What is the probability BOTH are blue
5/10 x 4/9= 20/90= 2/9
if an event is certain, its probability is ?
1
your friend and you randomly pick a movie. probability you both choose the same one out of 5?
1/5
A spinner has 4 equal sections: red,blue, green, yellow. probability of landing on green?
1/4
Flip a coin twice. What's the probability you get heads both times?
1/2 x 1/2= 1/4
a deck has 52 cards. you draw one card and don't replace it. what is the e probability of drawing a heart first, then a club second?
(13/52) x (13/51)= 169/2652= 13/204
if an event is impossible, its probability is?
if an event is impossible, its probability is?
a small raffle has 20 tickets and you bought 2. what's your chance of winning?
2/20= 1/10
A jar has 2 green, 2 red, and 6 blue marbles. Probability of picking blue?
6/10= 3/5
roll dice twice. Probability BOTH land on 6?
1/36
a bowl as 2 red candies, 3 green candies, and 1 purple candy (6 total). If you pick two candies without replacing them, what is the probability you pick green first and purple second?
(3/6) x (1/5)= 3/30= 1/10
convert 1/4 to a percent
25%
you choose a random number from 1-10 probability you pick 7?
1/10
A bag has 5 candies: 3 taffy, 2 sour patch, 4 Skittles, 3 nerds, and 4 Lemonheads. What is the probability of picking up a Lemonhead?
4/16= 1/4
Abox has 3 red, 2 green, and 1 yellow marble. you pick a marble, replace it, then roll a die. What is the probability you pick green and then roll a number less than 3?
(2/6) x (2/6)= 4/36= 1/9
a bag has 5 marbles. you pick 1, keep it, and pick another. Why is this dependent?
the first pick changes the second pick's probability
convert 3/5 to a decimal.
0.6
you randomly choose a meal from 4 options. probability of any one?
1/4