3/5 * X = 15
3/5 ÷3/5 * X = 15 ÷ 3/5
X = 25
The total length is 25 miles
Answer:
a) <em>Z-score = 0.75</em>
b) <em>Z-score = -32.833</em>
Step-by-step explanation:
<u><em>Step(i):-</em></u>
Given that mean of the Population = 33
Given a standard deviation of the Population = 12
Let 'X' be a random variable in a normal distribution
Let 'X' = 42
<u><em>Step(ii):-</em></u>
<em> </em>
<em></em>
<em> </em>
<em></em>
<u><em>Step(iii):-</em></u>
<em>Given that mean of the Population = 89</em>
Given a standard deviation of the Population = 1
Let 'X' be a random variable in a normal distribution
Let 'X⁻ = 82
<em> </em>
<em></em>
<em> </em>
<em></em>
<em>Z-score = -32.833</em>
<em></em>
Life expectancy of dollar bill = d
life expectancy of coin = c
d = 1/20 c
substitute value in for c (30)
d = 1/20 * 30
d = 30/20
d = 1.5
life expectancy of a dollar bill = 1.5 years