Answer:
-0.352
Explanation:
Total number of raffle tickets sold = 14,500
1 grand prize of $6,600, 3 prizes of $800, 3 prizes of $65 and 10 prizes of $20.
Therefore,
Probability of winning 1 grand prize of $6,600 = [tex]\frac{1}{14,500}[/tex]
Probability of winning 3 prizes of $800 = [tex]\frac{3}{14,500}[/tex]
Probability of winning 3 prizes of $65 = [tex]\frac{3}{14,500}[/tex]
Probability of winning 10 prizes of $20 = [tex]\frac{10}{14,500}[/tex]
Expected value:
[tex]=[(\frac{1}{14,500}\times 6,600) + (\frac{3}{14,500}\times 800) + (\frac{3}{14,500}\times 65) + (\frac{10}{14,500}\times 20)] - 1[/tex]
[tex]=(0.455+0.166+0.013+0.014)-1[/tex]
= 0.648 - 1
= -0.352