the difference between a two - digit number and the number obtained by interchanging the positions of its digits is 54 . what is the difference between the two digits of that number ?
sol . let the ten ’ s digit be x and unit ’ s digit be y , then , ( 10 x + y ) - ( 10 y + x ) = 54 ⇔ 9 ( x - y ) = 54 ⇔ x - y = 6 answer c
divide(54, subtract(const_10, const_1))