Answer = 5 problems per minute
Because you do the number of problems divided by the minutes eg 35/7 = 5
The numbers of new CDs is 30 and the old CDs is 21.
To solve this problem, we have to write a system of equations in which we would know the numbers of each types of CD she bought.
<h3>System of Equations</h3>
This is used to solve a series or complex of word problems in which we can represent in a mathematical statements;
- Let n represents numbers of new CDs
- Let u represents numbers of old CDs
The equations can be represented as

Let's take equation (i)
Making n the subject of formula

we can put equation (iii) into equation (ii)

Let's put the value of u into equation (i)

From the calculations above, the numbers of new CDs is 30 and the old CDs is 21.
Learn more on system of equations here;
brainly.com/question/13729904
D.500 meters is an expression of distance in SI units.
2y+18=42
2y=24
y=12
Hope this helps!
Answer:
B.
Step-by-step explanation:
I got it correct on edginuity