Question

Sue set up a lemonade stand and sold 10 glasses of lemonade in the first hour. Her sales increased at the rate of 20% per hour for the next n hours. Which function represents the total number of glasses she sold in the nth hour? If the price of 1 glass of lemonade is $0.50, how much money did she earn in the nth hour?
The function that gives the total number of glasses sold in the nth hour is____, and the money she earned in the nth hour is____.

First blank-
A: f(n) = 10 x 1.2^n
B: f(n) = 10 - 1.2^n
C: f(n) = 10 + 1.2^n

Second blank-
A: 10 x 1.2^n
B: 0.5(10 x 1.2^n)
C: 10 x 2^n

Answer 1

The appropriate exponential function for the first question is

... A: f(n) = 10 × 1.2^n

To find the revenue from sales of that many glasses, we multiply by the sale price to get

... B: 0.5(10 × 1.2^n)