You roll a six-sided die and observe the number showing on the top side when the die comes to rest. What is the probability of observing:a. an even number? b. a number greater than 1? c. a number less than 6? d. a prime number?

Respuesta :

[tex]a)\frac{1}{2}b)\frac{5}{6}c)\frac{5}{6}d)\frac{1}{2}[/tex]

1) Considering that a six-sided dice has all these possible numbers as outcomes we can write our sample space:

[tex]1,2,3,4,5,6[/tex]

2) So let's calculate the Probabilities:

a) Even number.

Note that we have three even numbers

[tex]1,\mathbf{2},3,\mathbf{4},5,\mathbf{6}[/tex]

So we can write the Probability of Even numbers as:

[tex]P(\text{even)}=\frac{3}{6}=\frac{1}{2}[/tex]

Note that on the denominator, we place the total possible results, and on the numerator the favorable outcomes.

b) A number > 1

Since we've got 5 favorable events (numbers) greater than 1, we can write out:

[tex]P(>1)=\frac{5}{6}[/tex]

c) A number < 6

[tex]P(<6)=\frac{5}{6}[/tex]

Note that similarly to the previous item we have 5 favorable outcomes (1,2,3,4,5) in a total of 6 possible results.

d) A Prime number:

In a six-sided die we have the following prime numbers:

[tex]\mathbf{2},\mathbf{3},4,\mathbf{5},6[/tex]

So we have 3 favorable outcomes:

[tex]P(\text{prime)}=\frac{3}{6}=\frac{1}{2}[/tex]

And that is the answer