The mean of five numbers is 18. If one number is excluded, their mean is 16. The excluded number is:  

   (A) 25  

   (B) 26  

   (C) 27  

   (D) None of these 

Let’s analyze the problem:

Understanding the problem:

• We have 5 numbers.
• The average (mean) of these 5 numbers is 18.
• If we remove one number, the average of the remaining 4 numbers becomes 16.
• We need to find the excluded number.

Solution:

1. Total of the 5 numbers:
   • Mean of 5 numbers = 18
   • Total of 5 numbers = 18 * 5 = 90
2. Total of the remaining 4 numbers:
   • Mean of 4 numbers = 16
   • Total of 4 numbers = 16 * 4 = 64
3. Finding the excluded number:
   • The excluded number is the difference between the total of 5 numbers and the total of 4 numbers.
   • Excluded number = 90 – 64 = 26

Therefore, the excluded number is 26.

So, the correct answer is (B) 26.