if 4 people are selected from a group of 8 married couples , what is the probability that none of them would be married to each other ?
"if we are to select 4 people from 8 couples without any restriction , how many ways can we make the selection ? 16 ! / 4 ! 12 ! = 1820 if we are to select 4 people from 8 couples with restriction that no married couple can both make it to the group , only a representative ? 8 ! / 4 ! 4 ! = 70 but we know that to select a person from each couple , take 2 possibilities 70 * 2 * 2 * 2 * 2 = 1120 probability = desired / all possibilities = 1120 / 1820 = 8 / 13 answer : c"
multiply(multiply(multiply(divide(multiply(8, const_2), multiply(8, const_2)), divide(multiply(4, 4), subtract(multiply(8, const_2), const_1))), divide(subtract(multiply(4, 4), const_2), multiply(4, 4))), divide(subtract(subtract(multiply(4, 4), const_2), const_2), subtract(multiply(4, 4), const_1)))