Answer:
x = friends that paid discount price = 8
y = friends that paid regular price = 4
Step-by-step explanation:
Let
x = friends that paid discount price
y = friends that paid regular price
x + y = 12 (1)
6x + 8y = 80 (2)
From (1)
x = 12 - y
Substitute x = 12 - y into (2)
6x + 8y = 80 (2)
6(12 - y) + 8y = 80
72 - 6y + 8y = 80
- 6y + 8y = 80 - 72
2y = 8
y = 8/2
y = 4
Substitute y = 4 into (1)
x + y = 12 (1)
x + 4 = 12
x = 12 - 4
x = 8
x = friends that paid discount price = 8
y = friends that paid regular price = 4
Answer:
924m^3 is the volume of the rectangular prism
Answer: 19 years
Step-by-step explanation:
Given
Amount invested 
Rate of interest 
after 1-year amount becomes

After n years it is

Sum accumulated is 

Answer:
<h2> (-1,1)</h2>
Step-by-step explanation:
Given system is

If we graph, the solution would be the interception point between these two lines, because each linear equation represents a line. The lines are attached.
In the graph, you can observe that the solution is the point (-1,1), that is x = -1 and y = 1.
Now, if we want to solve this system by another method, we can just sum both equations and solve for <em>x</em>


Then, we replace this value in one equation to find the other value

Therefore, the solution is (-1,1)
Answer:
0.36 = 36/100 = 9/25
so the simplest form is 9/25