Answer:
[tex]P(60mph\ or\ 70mph) = 0.38[/tex]
[tex]P(x>65mph) = 0.62[/tex]
[tex]P(x \le 70mph) = 0.74[/tex]
Step-by-step explanation:
Given
Speed Limits --- States
60 mph ---------- 1
65 mph ----------- 18
70 mph ----------- 18
75 mph ---------- 13
Total -------------- 50
Solving (a): Probability of 60mph or 70mph
This is represented as:
[tex]P(60mph\ or\ 70mph)[/tex]
We only consider states with speed limits of 60 and 70mph.
So, we have:
[tex]P(60mph\ or\ 70mph) = P(60mph) + P(70mph)[/tex]
[tex]P(60mph\ or\ 70mph) = \frac{1}{50} + \frac{18}{50}[/tex]
Take L.C.M
[tex]P(60mph\ or\ 70mph) = \frac{1+18}{50}[/tex]
[tex]P(60mph\ or\ 70mph) = \frac{19}{50}[/tex]
[tex]P(60mph\ or\ 70mph) = 0.38[/tex]
Solving (b): Greater than 65mph
This is represented as:
[tex]P(x>65mph)[/tex]
We only consider states with speed limits of 70 and 75mph.
So, we have:
[tex]P(x>65mph) = P(70mph) + P(75mph)[/tex]
This gives:
[tex]P(x>65mph) = \frac{18}{50} + \frac{13}{50}[/tex]
Take L.C.M
[tex]P(x>65mph) = \frac{18+13}{50}[/tex]
[tex]P(x>65mph) = \frac{31}{50}[/tex]
[tex]P(x>65mph) = 0.62[/tex]
Solving (c): 70mph or less
This is represented as:
[tex]P(x \le 70mph)[/tex]
We only consider states with speed limits of 60, 65 and 70mph.
So, we have:
[tex]P(x \le 70mph) = P(60mph) + P(65mph) + P(70mph)[/tex]
This gives:
[tex]P(x \le 70mph) = \frac{1}{50} + \frac{18}{50} + \frac{18}{50}[/tex]
Take L.C.M
[tex]P(x \le 70mph) = \frac{1+18+18}{50}[/tex]
[tex]P(x \le 70mph) = \frac{37}{50}[/tex]
[tex]P(x \le 70mph) = 0.74[/tex]
