Answer:
10 kg
Step-by-step explanation:
In 3% concentration of 20 kg of seawater, there will be 
kg of salt.
So, if it is a 2% solution of seawater,
Then 2 kg salt will be there in 100 kg solution.
So, 0.6 kg salt will be there in 
kg of solution.
So, to make a solution from 3% to 2% we have to add (30 - 20) = 10 kg of water with a 20 kg solution. (Answer)
The surface area of a right rectangular prism is the sum of the areas of all six faces of the prism. To calculate the total surface area, you must calculate the area of each face, and then you add all six areas together. Each face is a rectangle. As a shortcut, you really only need to find at most three areas since each two opposite faces are congruent rectangles and have equal areas. Since the area of a rectangle is length times width, and they are both measured in linear measurements, such are meters or feet, the area of each face is in square meters or square feet. The total area is also measured n square meters or square feet. If you are painting a room, including all walls, the floor and the ceiling, it would be helpful to know the total surface area to calculate the amount of paint needed. Also, if you are wrapping a box that is shaped like a right rectangular prism, the the total surface area will tell you how much area of wrapping paper you need.
The volume of a right rectangular prism is the amount of three-dimensional space it occupies. To calculate it, you multiply the length by the width by the height. Since length, width, and height are linear measures, with units such as meters or feet, the volume is a cubic measure measured in cubic meters or cubic feet. If you have a certain volume of an item that you need to put in a box, then by knowing how to calculate the volume of the box, you can tell what size box you will need.
I have taken the test and I can confirm that the answer is
B. 15 m, 20 m, and 25 m.
Have a fantastic day!
Answer:
its a variety of selection techniques in which sample members are selected by chance
Step-by-step explanation:
This one is so easy that your brain refuses to accept it.
It's looking for a harder answer, but can't find it !
You're totally correct, as far you went. x² + 2x does = -1
Now add ' 1 ' to each side: x² + 2x + 1 = 0
Can you factor that quadratic ?
Can you mash it through the quadratic formula ?
Actually, it's the simplest possible perfect square.
x² + 2x + 1 = (x + 1)²
So the solutions of x² + 2x + 1 = 0 are both x = -1 .
Don't say anything.
I know it's embarrassing.
