Cards are drawn one-by-one at random from a well-shuffled pack of 52 playing cards until 2 aces are obtained from the first time. The probability that 18 draws are obtained for this is `3//34` b. `17//455` c. `561//15925` d. none of these

Options

A. `3//34`
B. `17//455`
C. `561//15925`
D. None of these

Answer

C

Explanation

18 draws are required for 2 aces. This means in the first 17 draws, there is one ace and 16 other cards, and 18th draw produces an ace. So, the required probability is
`(""^(48)C_(16)xx""^(4)C_(1))/(""^(52)C_(17))xx3/35=(561)/(15925)`