if 100 < x < 199 and 20 < y < 100 , then the product xy can not be equal to :
"correct answer : ( a ) determine the range of xy by multiplying the two extremes of each individual range together . the smallest value of xy must be greater than 100 * 20 . the largest value must be less than 199 * 100 . this means that 2000 < xy < 19,900 . ( a ) is outside of this range , so it is not a possible product of xy ."
add(100, const_1)