<u><em>Answer:</em></u>
5%
<u><em>Explanation:</em></u>
% she earned in interest can be calculated by calculating the % of increase in the balance
<u>We have:</u>
Original balance = $12,450
Amount of interest = $622.5
<u>This means that:</u>
new balance = 12,450 + 622.5 = $13,072.5
<u>Now, we can get the percentage of increase:</u>
% of increase = 
<u>Substitute with the values we have to get the percentage of interest earned as follows:</u>
% of interest earned = 
= 5%
Hope this helps :)
The slope of a line perpendicular to the line y=1, would be y=-1.
Answer:
D.) $12n + $8u = 112 ;u = 4 + n
Step-by-step explanation:
Given that :
Cost per new books (n) = $12
Cost per used book (u) = $8
Total revenue earned = $112
store sold 4 more used books than new books
Hence,
Total revenue should be :
Revenue from new books + Revenue from used book = total revenue
Revenue from new books = $12 * n = $12n
Revenue from used books = $8 * n = $8n
$12n + $8u = 112
Number of books sold :
Number of used books sold = 4 + number of new books sold
u = 4 + n
