Answer:
11. always
12. always
13. always
14. never
15. never
16. always
17. always
18. sometimes
19. sometimes
20. never
Step-by-step explanation:
11. A line can be defined by at least two points
12. A plane can be defined by at least three points
13. If two planes intersect, then they form a line at the intersection.
14. If two lines intersect, then they form a point at the intersection (not a segment).
15. A line does not have any endpoints (infinite in both ways).
16. If two planes are not parallel they will always intersect.
17. If two lines are not parallel they will always intersect.
18. Two points are sometimes collinear. It depends on where they are.
19. Two points are sometimes coplanar. It depends on where they are.
20. Ray MN and NM are not the same ray because the end points are different.
Let x represent the amount of 10% solution used.
Let y represent the amount of 25% solution used.
Since 30 liters of 15% solution are being made, our first equation is
x + y = 30
Now we deal with the actual peroxide in each solution.
x liters of 10% peroxide contain 0.1x liters of peroxide.
y liters of 25% peroxide contain 0.25y liters of peroxide.
30 liters of 15% peroxide contain 0.15 * 30 = 4.5 liters of peroxide.
From this information, we can write our second equation.
0.1x + 0.25y = 4.5
We have a system of equations:
x + y = 30
0.1x + 0.25y = 4.5
Multiply the first equation by -0.25 and add to the second equation.
-0.25x - 0.25y = -7.5
0.1x + 0.25y = 4.5
---------------------------
-0.15x = -3
x = 20
Answer: 20 liters
Answer:
C
Step-by-step explanation:
Try multiplying all the sides.
Step-by-step explanation:
A compound contains atoms of different elements chemically combined together in a fixed ratio. An element is a pure chemical substance made of same type of atom. ... Compounds contain different elements in a fixed ratio arranged in a defined manner through chemical bonds. They contain only one type of molecule.
