document.write( "Question 1197565: A pair of 6 sided dice are tossed. What is the probability that at least one of the dice has a value greater than or equal to 5? \n" ); document.write( "
Algebra.Com's Answer #830873 by math_tutor2020(3816)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "There are 6 sides on each dice, giving 6*6 = 36 outcomes.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's call the dice A and B \n" ); document.write( "Let's have die A roll to 4 or smaller. Same goes for die B. \n" ); document.write( "There are 4*4 = 16 outcomes where both dice are 4 or smaller.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "That must mean 36-16 = 20 outcomes are when either \n" ); document.write( "A = 5 or 6 \n" ); document.write( "OR \n" ); document.write( "B = 5 or 6 \n" ); document.write( "or both scenarios happen\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We can confirm this with a chart \n" ); document.write( "
\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "There are 6 X's in row 5 and 6 X's in row 6 \n" ); document.write( "That's 6+6 = 12 X's total so far. \n" ); document.write( "We have 6 X's in column 5 and 6 X's in column 6 \n" ); document.write( "That's another 6+6 = 12 X's \n" ); document.write( "We're up to 12+12 = 24 \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "But in the bottom right hand corner, we're double counting those four X's since they are in the overlapped region of the four columns mentioned. \n" ); document.write( "We need to subtract off 4 to correct for this erroneous double counting. \n" ); document.write( "24-4 = 20\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Or note that the blank portion of the table is 4 rows tall and 4 columns across. \n" ); document.write( "This represents the 4*4 = 16 cases where both dice are 4 or smaller, as mentioned earlier. \n" ); document.write( "This then gives us the 36-16 = 20 copies of X in total.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "----------------------------------------------------\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The summary so far is that there are 20 ways to have at least one of the dice be 5 or 6.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "This is out of 36 ways to roll two dice \n" ); document.write( "20/36 = (4*5)/(4*9) = 5/9\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Answer: 5/9 \n" ); document.write( " \n" ); document.write( " |