taiwan-gsat 2024 Q4

taiwan-gsat · Other · ast__math-a 8 marks Roots of polynomials Existence or counting of roots with specified properties
A game company will hold a lottery activity. The company announces that each lottery draw requires using one token, and the winning probability for each draw is $\frac{1}{10}$. A certain person decides to save a certain number of tokens and start drawing after the activity begins, stopping only when all tokens are used. Select the correct options.
(1) The expected value of the number of draws needed for the person to win once is 10
(2) The probability that the person wins at least once in two draws is 0.2
(3) The probability that the person does not win in 10 draws is less than the probability of winning in 1 draw
(4) The person must save at least 22 tokens to guarantee a winning probability greater than 0.9
(5) If the person saves sufficiently many tokens, the winning probability can be guaranteed to be 1
A game company will hold a lottery activity. The company announces that each lottery draw requires using one token, and the winning probability for each draw is $\frac{1}{10}$. A certain person decides to save a certain number of tokens and start drawing after the activity begins, stopping only when all tokens are used. Select the correct options.\\
(1) The expected value of the number of draws needed for the person to win once is 10\\
(2) The probability that the person wins at least once in two draws is 0.2\\
(3) The probability that the person does not win in 10 draws is less than the probability of winning in 1 draw\\
(4) The person must save at least 22 tokens to guarantee a winning probability greater than 0.9\\
(5) If the person saves sufficiently many tokens, the winning probability can be guaranteed to be 1