The mean age of 15 pupils in a class is 14.2 years. One new pupil joined the class and the mean changed to 14.1 years. Calculate the age of the new pupil.
-
A.
12.4 years -
B.
12.6 years -
C.
13.2 years -
D.
14.1 years
Correct Answer: Option B
Explanation
(Mean = frac{text{sum of ages}}{text{no of pupils}})
Let the sum of the ages of the 15 pupils be x and the sum of the 16 pupils be y.
(frac{x}{15} = 14.2 implies x = 14.2 times 15 = 213)
(frac{y}{16} = 14.1 implies y = 14.1 times 16 = 225.6)
(text{Age of new pupil} = 225.6 – 213 = 12.6)