if p ( a ) = 2 / 15 , p ( b ) = 4 / 15 , and p ( a â ˆ ª b ) = 12 / 15 find p ( b | a )
"p ( b | a ) = p ( a â ˆ ª b ) / p ( a ) p ( b | a ) = ( 12 / 15 ) / ( 2 / 15 ) = 6 . e"
divide(divide(12, 15), divide(2, 15))