The average height of 15 students of a class is 136.5 cm. When one more student joins the class, the average height becomes 135.6 cm. What is the height of the new student?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 122.1 cm
The total height is the average multiplied by the number of students. The new total minus the old total is the height of the new student.
Total height of 15 students \(=15\times136.5=2047.5\) cm
Total height of 16 students \(=16\times135.6=2169.6\) cm
Height of the new student \(=2169.6-2047.5=122.1\) cm
The new student is 122.1 cm tall.