average age of students of an adult school is 42 years . 120 new students whose average age is 32 years joined the school . as a result the average age is decreased by 4 years . find the number of students of the school after joining of the new students .
"explanation : let the original no . of students be x . according to situation , 42 x + 120 * 32 = ( x + 120 ) 36 ⇒ x = 80 so , required no . of students after joining the new students = x + 120 = 200 . answer : d"
multiply(divide(subtract(multiply(add(32, 4), 120), multiply(120, 32)), subtract(42, add(32, 4))), 4)