Question

The average cell phone bill per year was $650 in 2009. If the average cost each year is about 109.2% of the previous year (9.2% increase), what will a person pay total for a cell phone for 2009-2018? (Round to nearest dollar.) Question 9 options: $8535 $6500 $7098 $9970 Save

Answer 1

i believe the answer is $709.8 but $7098 seems the closest

Answer 2

$ 8535

Explanation:

Given,

The average cell phone bill in 2009 = $ 650,

Since, the average cost each year is about 109.2% of the previous year,

Thus, there is a GP, that shows the average cell phone bill of every year,

That having first term, a = 650,

Common difference, d = 109.2 % = 1.092,

Thus, the total cell phone bill for 2009-2018 = Sum of the 9 terms of the above G.P.

`S_(n)=(a(r^n-1))/(r-1)`

`S_(9)=(650(1.092^9-1))/(1.092-1)`

`=8534.95058244`

`\approx 8535`

Hence, The person will pay approximately $ 8535 for 2009 - 2018.

First option is correct.