in a certain lottery , the probability that a number between 12 and 20 , inclusive , is drawn is 1 / 6 . if the probability that a number 12 or larger is drawn is 1 / 3 , what is the probability that a number less than or equal to 20 is drawn ?
"you can simply use sets concept in this question . the formula total = n ( a ) + n ( b ) - n ( a and b ) is applicable here too . set 1 : number 12 or larger set 2 : number 20 or smaller 1 = p ( set 1 ) + p ( set 2 ) - p ( set 1 and set 2 ) ( combined probability is 1 because every number will be either 12 or moreor 20 or lessor both ) 1 / 3 + p ( set 2 ) - 1 / 6 = 1 p ( set 2 ) = 5 / 6 answer ( e )"
subtract(add(12, divide(12, 6)), divide(1, 6))