At a fete, cards bearing numbers 1 to 1000, one number on one card, are put in a box. Each player selected one card at random and that card is not replaced. If the selected card has a perfect square greater than 500, the player wins a prize. What is the probability that
(i) the first player wins a prize?
(ii) the second player wins a prize, if the first has won?
Given that, at a fete, cards bearing numbers 1 to 1000 one number on one card, are put in a box. Each player selects one card at random and that card is not replaced so, the total number of outcomes are n(S) = 1000
If the selected card has a perfect square greater than 500, then player wins a prize.
(i) Let E1 = Event first player wins a prize = Player select a card which is a perfect square greater than 500
= {529, 576, 625, 729, 784, 841, 900, 961}
= {(23)2,(24)2,(25)2,(26)2,(27)2,(28)2,(29)2,(30)2,(31)2}
∴ n(E) = 9
So, required probability 
(ii) First, has won i.e., one card is already selected, greater than 500, has a perfect square. Since, repetition is not allowed. So, one card is removed out of 1000 cards. So, number of remaining card is 999.
∴ Total number of remaining outcomes, n(S’) = 999
Let E2 be the event that the second player wins a prize, if the first has won.
Then, the remaining cards has a perfect square greater than 500 = 8
So, required probability 