20 and 21 is your answer
20 + 21 = 41
hope this helps
When you add a zero to the problem, it shows you are now multiplying in the double-digits. Let's say you are multiplying 12x12. First you cover up the one then multiply them. Then cover up the two and you have 10. When you multiply them, it ends in a zero. Don't think of it as adding a zero but adding to products.
Answer:
ft³
Step-by-step explanation:
First, let's figure out how to get the <em>volume </em>of a sphere from its <em>surface area</em>. If r is the radius of our sphere, then
The formula for a sphere's surface area is
The formula for a sphere's volume is 
So to get from area to volume, we have to <em>divide the area by 3 </em>and then <em>multiply it by r.</em> Mathematically:

Before we solve for V though, we need to find the radius of our sphere. Thankfully, we're given the surface area -
ft² - so we can use the area formula to find that radius:

And now that we have our radius, we can put it into our volume formula to find
ft³
Answer:
3 = 95, 4 = 85, if a and b are parallel
Step-by-step explanation:
Fit Fast: a set feet per class => y = Ax
Stepping Up: a monthly fee plus an additioal fee per class => h = Bx + C
You can discard the second and the fourth systems because they do not have the form established from the statement.
The first system produce an obvious result given that is represents an option that is always better than the other 5.5x will be lower than 7.5x + 10 for any positive value of x, and so there is no need to make any comparission.
The third system is
y = 7.5x and y = 5.5x + 10 which need to be solved to determine when one rate is more convenient than the other.
Answer: y = 7.5x and y = 5..5x + 10