The average age of 6 members of a family is 20 years. If the age of the servant is included, then the average age increase by 25%. What is the age (in years) of the servant?

Step 1: Understand the initial setup

• Average age of 6 family members = 20 years
• Total age of 6 members = 6 × 20 = 120 years
• After including servant, total members = 7
• New average = 20 + 25% of 20 = 20 + 5 = 25 years

Step 2: Calculate the total age of 7 people

New total age = 7 × 25 = 175 years

Step 3: Calculate the age of the servant

Age of servant = New total age - Total age of 6 family members
               = 175 - 120
               = 55 years

Answer: 55 years

The age of the servant is 55 years.

This question is a good example of applying average concepts with a twist — it tests understanding of how an additional value impacts the average of a group. It is relevant for students preparing for aptitude tests, and helps in strengthening problem-solving using arithmetic operations.