Answer:

Step-by-step explanation:
=> 78% makes:
=> 
<u><em>In simplest form:</em></u>
=>
Answer: 6.8%
Step-by-step explanation:
We need to find both percentage so we can determine the increase.
Finding percentage of $10 return: 1% return
Finding percentage of $78 return: 7.8% return
To find the percent increase we do 7.8%-1.0% = 6.8%
Multiply 15 x 3.14. You'll get 47.1. Thats the area
The slope is -3 and the y-intercept is -1