Hi help me plz answer this question

The holiday party will cost $160 if 8 people attend.if there are 40 people who attend the party, how much will the holiday party cost

The population of a small rural town in the year 2006 was 2,459. the population can be modeled by the function below, where f(x residents and t is the number of years elapsed since 2006. f(t) = 2,459(0.92)

Use sigma notation to represent the following series for 9 terms.