The probability of an event P(n), is equal to the number of the outcomes of that event n(E), divided by the total number of outcomes, or the sample space, n(S)
so [tex]P(n)= \frac{n(E)}{n(S)} [/tex]
[tex]P(truck need rapair within the first year)=[/tex]
[tex] \frac{n(truck need rapair within the first year)}{n(trucks)} = \frac{105}
{420}= 0.25[/tex]
The probability of an event = 1 - probability of the same event not to happen
so P(not need repair within the first year)=1-0.25=0.75
Answer: a) 0,25; b) 0,75
