Question

St. Mary's Church is holding a raffle in which 1172 tickets have been sold at a cost of $2.00 each. Three prizes will be awarded: 1 for S500;1 for $250; 1 for $125. If you buy one ticket, then your expected value for this raffle is $ You do not need to include the dollar sign (S) with your answer. Give your answer as numerical value rounded to 2 decimal places. No $ sig?n

Answer 1

Answer:

- 1.25 ( approx )

Step-by-step explanation:

Given,

Total tickets = 1172,

In which every ticket costs $ 2, also, three prizes will be awarded 1 for $ 500, 1 for $250 and 1 for $125.

$\because \text{Probability}=\frac{\text{Number of favourable outcomes}}{\text{Total outcomes}}$

Thus, we can make a table that represents the given situation,

Number of tickets            1                   1                      1              1169

Probability of ticket        1/1172          1/1172             1/1172         1169/1172

Price of ticket                  $ 500          $ 250            $ 125            - $ 2

( Note : Negative sign shows the loss, i.e. if we could not get any price then we have a loss of $ 2 )

Thus, the expected value of a ticket

$=\frac{1}{1172}\times 500+\frac{1}{1172}\times 250+\frac{1}{1172}\times 125+\frac{1169}{1172}\times -2$

$=\frac{500}{1172}+\frac{250}{1172}+\frac{125}{1172}-\frac{2338}{1172}$

$=-1.24829351536$

$\approx -1.25$