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There are two different raffles you can enter. Raffle A is for a $280\$280 prize. Out of 100100 tickets, each costing $15\$15, one ticket will win the prize, and the rest will win nothing. In raffle B, one ticket out of 100100 will win a $560\$560 prize, and one ticket will win a $490\$490 prize. The remaining tickets will win nothing. Each ticket costs $20\$20. Which raffle is a better deal?\newline(A)Raffle A\newline(B)Raffle B

Full solution

Q. There are two different raffles you can enter. Raffle A is for a $280\$280 prize. Out of 100100 tickets, each costing $15\$15, one ticket will win the prize, and the rest will win nothing. In raffle B, one ticket out of 100100 will win a $560\$560 prize, and one ticket will win a $490\$490 prize. The remaining tickets will win nothing. Each ticket costs $20\$20. Which raffle is a better deal?\newline(A)Raffle A\newline(B)Raffle B
  1. Calculate Expected Value Raffle A: Calculate the expected value for Raffle A.\newlineExpected value = (\text{Probability of winning} \times \text{Prize value}) - (\text{Cost of ticket})\newlineExpected value for Raffle A = (1100×$(280))$(15)\left(\frac{1}{100} \times \$(280)\right) - \$(15)\newlineExpected value for Raffle A = $(2.80)$(15)\$(2.80) - \$(15)\newlineExpected value for Raffle A = $(12.20)-\$(12.20)
  2. Calculate Expected Value Raffle B: Calculate the expected value for Raffle B.\newlineExpected value = (Probability of winning the first prize ×\times First prize value) + (Probability of winning the second prize ×\times Second prize value) - (Cost of ticket)\newlineExpected value for Raffle B = (1100×$560)+(1100×$490)$20\left(\frac{1}{100} \times \$560\right) + \left(\frac{1}{100} \times \$490\right) - \$20\newlineExpected value for Raffle B = $5.60+$4.90$20\$5.60 + \$4.90 - \$20\newlineExpected value for Raffle B = $10.50$20\$10.50 - \$20\newlineExpected value for Raffle B = $9.50-\$9.50
  3. Compare Expected Values: Compare the expected values of both raffles to determine which is a better deal.\newlineRaffle A has an expected value of $12.20-\$12.20 and Raffle B has an expected value of $9.50-\$9.50.\newlineSince the expected value is less negative for Raffle B, it is the better deal.

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