The answer is the option C and the option D, which are:
C. Double the number of pages in the book.
D. The age of my friend.
The explanation for this problem is shown below:
By definition, a variable is an unkown quantity. In the Option A the quantity is given: 
seconds in a minute. In the option B you know the quantity too, which is 
years old. But the option C and the option D does not give any quantity, you don't know the number of pages in the book or the age of the friend yet. Therefore, the answer is the options C and D.
Answer:
The mother (Rhoda) is 46 years old.
The daughter (Tenica) is 18 years old
Step-by-step explanation:
Let the age of the mother (Rhoda) be m
Let the age of the daughter (Tenica) be d.
The sum of Rhonda and her daughter Tenica’s age is 64. This can be written as:
m + d = 64 ... (1)
The difference in their ages is 28. This can be written as:
m – d = 28 ... (2)
From the above illustrations, the equation obtained are:
m + d = 64 ... (1)
m – d = 28 ... (2)
Solving by elimination method:
Add equation 1 and 2 together
. m + d = 64
+ m – d = 28
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
2m = 92
Divide both side by 2
m = 92/2
m = 46
Substitute the value of m into any of the equation to obtain the value of d. Here, we shall use equation 1
m + d = 64
m = 46
46 + d = 64
Collect like terms
d = 64 – 46
d = 18
Therefore, the mother (Rhoda) is 46 years old and the daughter (Tenica) is 18 years old.
The answer is the first one.
Knowing that population density is like a rate, people per a given area, you would take the amount of people and divide by the area.
3.11E7/7.69E6 = 4.02 people per km squared.
Also the “E” is another way to write times 10 to a power and I recommend using that notation when plugging it into a calculator.
Putting a = 6 and b= 3/2 in eqn. (1) the required equation is:-
x /6 + 2.y/3 = 1. or, x + 4y = 6. Answer.
1. (x , y) → (kx , ky) = Dilation ; similar image
2. (x , y) → (y , -x) = Rotation 90 counterclockwise ; congruent
3. (x , y) → (-x , y) = Reflection over y-axis ; congruent
4. (x , y) → (-x , -y) = Rotation 180 ; congruent
5. (x , y) → (x, -y) = Reflection over x-axis ; congruent
6. (x , y) → (-y , x) = Rotation 90 clockwise ; congruent
7. (x , y) → (x + a , y + b) = Translation ; congruent
Hope this helps :)
