Question

Please help!

You flip a coin, and then roll a number cube twice. (a number cube 1-6) Find the probability of the event.
1) Flipping head, rolling a 5, and rolling a 2
2) Flipping tails, rolling an odd number, and rolling a 4
3) Flipping head, not rolling a 2, and rolling an even number

Answer 1

1) 1.4%

2) 8.3%

3) 20.8%

Explanation:

Alrighty! You are looking at some compound probability problems.

The trick with these is to figure out the probability of each piece of an event, and then multiply those together to get the overall probability.

Quick note about notation: p(event A) is short hand for saying "The probability of event A is....."

1) Flipping head, rolling a 5, and rolling a 2

P(flipping heads) = 1/2

p(rolling a 5) = 1/6

p(rolling a 2) = 1/6

so: (1/2) x (1/6) x (1/6) = 1/72 or about 1.4%

2) Flipping tails, rolling an odd number, and rolling a 4

p(flipping tails) = 1/2

p(rolling an odd number) = 3/6

p(rolling a 4) = 1/6

so: (1/2) x (3/6) x (1/6) = 3/72 or about 8.3%

3) Flipping head, not rolling a 2, and rolling an even number

p(flipping heads) = 1/2

p(not rolling a 2) = 5/6

p(rolling and even number) = 3/6

so: (1/2) x (5/6) x (3/6) = 15/72 or about 20.8%