document.write( "Question 1146498: Three cards are drawn at random without replacement. Without knowing the values of the first two cards, what is the probability of the third card having value of 10 and/or being a face card? \n" ); document.write( "
Algebra.Com's Answer #767798 by VFBundy(438) You can put this solution on YOUR website! There are 16 cards that have a value of 10: the 10, J, Q, and K of all four suits. \n" ); document.write( " \n" ); document.write( "Chances both of the first two cards have a \"10\" value = 16/52 * 15/51 = 20/221 \n" ); document.write( " \n" ); document.write( "Chances first card has a \"10\" value and second card does not have a \"10\" value = 16/52 * 36/51 = 48/221 \n" ); document.write( " \n" ); document.write( "Chances first card does not have a \"10\" value and second card has a \"10\" value = 36/52 * 16/51 = 48/221 \n" ); document.write( " \n" ); document.write( "Chances neither of the first two cards have a \"10\" value = 36/52 * 35/51 = 105/221 \n" ); document.write( " \n" ); document.write( "Continuing... \n" ); document.write( " \n" ); document.write( "20/221 of the time, two \"10\" cards have been drawn, leaving 14 \"10\" cards remaining out of the 50 remaining cards. Or, a 14/50 chance the third card will be a \"10\" card. \n" ); document.write( " \n" ); document.write( "96/221 of the time, one \"10\" card has been drawn, leaving 15 \"10\" cards remaining out of the 50 remaining cards. Or, a 15/50 chance the third card will be a \"10\" card. (The 96/221 number comes from adding together the chance where a \"10\" card is drawn first and the chance where a \"10\" card is drawn second.) \n" ); document.write( " \n" ); document.write( "105/221 of the time, zero \"10\" cards have been drawn, leaving all 16 \"10\" cards remaining out of the 50 remaining cards. Or, a 16/50 chance the third card will be a \"10\" card. \n" ); document.write( " \n" ); document.write( "So... \n" ); document.write( " \n" ); document.write( "20/221 of the time, there is a 14/50 probability the third card will be a \"10\" card. \n" ); document.write( " \n" ); document.write( "96/221 of the time, there is a 15/50 probability the third card will be a \"10\" card. \n" ); document.write( " \n" ); document.write( "105/221 of the time, there is a 16/50 probability the third card will be a \"10\" card. \n" ); document.write( " \n" ); document.write( "The math is as follows: \n" ); document.write( " \n" ); document.write( "(20/221) * (14/50) = 28/1105 \n" ); document.write( "(96/221) * (15/50) = 144/1105 \n" ); document.write( "(105/221) * (16/50) = 168/1105 \n" ); document.write( " \n" ); document.write( "Add together 28/1105 + 144/1105 + 168/1105 and you get 340/1105. This fraction reduces to 4/13. \n" ); document.write( " \n" ); document.write( "So, there is a 4/13 probability the third card will be a \"10\" card. |