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:
20.0%
Step-by-step explanation:
The last 30 presidents of America starts from the 16th president, Abraham Lincoln and ends with the current and 45th president, Donald Trump.
The presidents that are 60 and above years during this period include
Donald Trump, Goerge H. W. Bush, Roland Regan, Gerald Ford, Dwight D. Eisenhower and Harry S. Truman.
Making 6 of them out of 30
The percentage is given by
Number of presidents aged 60 and above×100/Total number of presidents
6×30/100=20%
Answer:
k =4
Step-by-step explanation:
5k-2k=12
Combine like terms
3k = 12
Divide each side by 3
3k/3 = 12/3
k = 4
Answer:
Step-by-step explanation:
From the question we are told that:
Dimension of ABC
A=9
B=11
C=110
Dimension of FED
D=231
Generally the equation for the similar triangles is mathematically given by
Therefore solving for F
Therefore solving for E
Measure of 
Measure of 
Answer:
1. x = -7
2. x = 6/13
3. x = 7/12
Step-by-step explanation:
1. x = 21 / -3
x = -7
2. 13x = 6
x = 6 / 13
x = 6/13
3. -12x = -7
x = -7 / -12
x = 7/12
<em>Hope that helps!</em>
