If the average of the four consecutive odd numbers is 42, find the sum of the digits of the largest of these numbers.

Correct option is D

Given:
Average of four consecutive odd numbers = 42
Concept Used:
Consecutive odd numbers increase by 2. For example, if the first odd number is x the next three consecutive odd numbers will be x + 2, x + 4 and x + 6.
Solution:
Let the four consecutive odd numbers be:
x, x + 2,  x + 4, x + 6
$$\text{Average} = \frac{x + (x + 2) + (x + 4) + (x + 6)}{4} = 42$$​​
$$\frac{4x + 12}{4} = 42$$​​
x + 3 = 42
x = 42 - 3 = 39
The four consecutive odd numbers are:
39, 41, 43,  45
The largest number is 45.
Sum of its digits = 4 + 5 = 9

Thus, option (D) is right.