Using proportions, it is found that the mean time between arrivals is of 12 minutes.
The rule of three is:
5 trucks - 60 minutes
1 truck - x minutes
Applying cross multiplication:
[tex]5x = 60[/tex]
[tex]x = \frac{60}{5}[/tex]
[tex]x = 12[/tex]
The mean time between arrivals is of 12 minutes.
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