the average salary of the employees in a office is rs . 120 / month . the avg salary of officers is rs . 420 and of non officers is rs 110 . if the no . of officers is 15 , then find the no of nonofficers in the office .
"let no . of non - officers be x 15 * 420 + x * 110 = ( x + 15 ) 120 x = 450 d"
divide(subtract(multiply(15, 420), multiply(15, 120)), subtract(120, 110))