Question

The average annual salary of the employees of a company in the year 2005 was ninety thousand dollars. It increased by the same factor each year and in 2006, the average annual salary was $91,200. Let f(x) represent the average annual salary, in thousand dollars, after x years since 2005. Which of the following best represents the relationship between x and f(x)?

f(x) = 91.2(1.013)x
f(x) = 90(1.013)x
f(x) = 91.2(2.2)x
f(x) = 90(2.2)x

Answer 1

Answer: the second option (but you need to show the operator ^)

2005 --- 90,000
2006 --- 91,200

Factor 91,200 / 90,000 = 1.013

year salary

2005 --- 90,000 = (90,000) (1.013)^0
2006 --- 90,000 (1.013)^1
2007 --- 90,000 (1.013)^2

f(x) = 90,000 (1.013)^x

if you show the numbers in thousands 90,000 converts in 90

f(x) = 90 (1.013)^x