mathsucksalot123 Group Title Rock music accounted for 30.5% of the total sales of recorded music in 1999 , and 20.4% of the total sales of recorded music in 2009 . Find the average rate of change of the percentage of sales of rock music from 1999 to 2009 . Round to the nearest hundredth of a percent. Note that the percentage sign is already given in the answer, so you do not need to enter it. The average rate of change is . 3 years ago 3 years ago

1. helpingtutors

(30.5 - 20.4)/10 = 10.1/10 = 1.01

2. mathsucksalot123

i tried that. it says its wrong :(

3. satellite73

that is because your answer should be negative. sales declined over the ten year period

4. satellite73

$\frac{30.5-20.4}{1999-2009}=\frac{10.1}{-10}$

5. mathsucksalot123

thanks

6. satellite73

yw