Q. The average of 20 numbers is 15 and the average of first five is 12. The average of the rest is:
Answer: 16
Notes: If the average of remaining numbers be x, then 20 $ \times$ 15 = 5 $ \times$ 12 + 15 x => 300 = 60 + 15 x => 15 x = 300 – 60 = 240 $ => x = \frac{240}{15} = 16$ Hence option [D] is correct answer.