Question 7

Explanation

Arithmetic Sequence Identification

Based on the information, Mr. Brikson's salary forms an arithmetic sequence with:

• Salary this year (age $40$) as the first term ($a$): $a = 15.750.000$
• Annual salary increase as the common difference ($b$): $b = 750.000$

We need to find the salary at age $54$. The difference in years from age $40$ to $54$ is:

Since the salary increases every year, the salary at age $54$ is the initial salary plus $14$ increases.

Salary Calculation

Using the formula for the $n$-th term (where $n$ here represents the 15th year of the sequence, i.e., after 14 increases):

Substituting the values:

So, Mr. Brikson's salary when he is $54$ years old is $\text{Rp}26.250.000,00$.