A rational number is any number that can be expressed as the quotient or fraction
Part A
Use the binomial probability distribution formula.
p = 0.54 = probability of getting a purple marble
n = 5 = sample size
x = 2 = number of purple we want to get

The
portion is from the nCr combination formula. The exclamation marks indicate a factorial.
Alternatively, you could use Pascal's Triangle for that portion.
<h3>Answer: 0.283831776</h3>
This decimal value is exact. Round it however you need to.
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Part B
To find the expected value, aka the mean, we multiply the sample size and probability of getting a purple marble on any single selection.
n*p = 5*0.54 = 2.7
<h3>Answer: 2.7</h3>
<em>Hello!</em>
<em>17.45 as a mixed fraction is </em><em>17 9/20</em><em>.</em>
<em>If this is not correct, please comment below and I will try my best to find the right answer.</em>
270 miles be 90+90+90 equals 270 and thats the answer