The term "closed" in math means that if you take two items from a set, do some operation, then you'll always get another value in the same set (sometimes you may get the same value as used before). For example, adding two whole numbers leads to another whole number. We therefore say "the set of whole numbers is closed under addition". This applies to integers as well because integers are positive and negative whole numbers. So we can say that integers are closed under addition.
Integers are not closed under division. Take two integers like 2 an 5 and divide: 2/5 = 0.4 which is not an integer. Integers don't have decimal parts.
The set of whole numbers is {0,1,2,3,...} and we can subtract the two values 1 and 2 to get 1-2 = -1. The order matters here. Subtracting a larger value from a smaller leads to a negative. The value -1 is not in the set of whole numbers. So we can say that whole numbers is not closed under subtraction
Finally, the set of irrational numbers is closed under addition. Adding any two irrational numbers leads to another irrational number. For instance, pi+sqrt(2) = 3.142 + 1.414 = 4.556; I'm using rounded decimals as approximate values. An irrational number is one where we cannot write it as a fraction of integers. Contrast that with a rational number in which we can write it as a fraction of integers. Example: 10 = 10/1 is a rational number.
Area of a circle is found using the formula: A = PI x r^2 where r is the radius of the circle, which is half the diameter.
Using the information in the problem you have:
A= PI x 15^2
A = PI x 225
A = 706.5 sq. In.
Answer:
5x -12 = 3x +8 (set the two = each other because they are the same length)
2x- 12= 8 (subtract 3x from both sides)
2x = 20 (add 12 to both sides)
x=10 (what x= for both expressions)
5(10) -12 (plug it into the first one to see what the length is and to see they're =
50 - 12 ( I already multiplied, now subtract)
38 (what the length of TR is)
3(10) +8 (plug it in again but into the other expression)
30+8 (multiply and add)
38 (the two have the same answer, so the x-value is correct.)
38+38= 76 (add the lengths of RS and TR and you get the length of TS)
Step-by-step explanation:
I hope this helps :)
Answer:
option (D) 16.5
Step-by-step explanation:
Data provided:
Sleep time of , X = 15.9 is at the 10th percentile
Standard deviation, σ = 0.5 hour
also,
10th percentile of normal distribution is
Z = F⁻¹(0.10)
or
Z = - 1.28 (Using Standard Normal distribution)
Now,
or
X = μ + ( σ × Z )
or
μ = X - ( σ × Z )
on substituting the respective values, we get
μ = 15.9 - 0.5 × (-1.28)
or
μ = 16.5
Hence, the correct answer is option (D) 16.5
Answer:
200,300,290,320,340
Step-by-step explanation:
If the mean of five numbers = 290
Then the total sum of the five numbers should be= 290*5
= 1450
an example of a set of five different numbers whose mean is 290
= 200,300,290,320,340
Summation of the above
=( 200+300+290+320+340)
= 1450
So the above set of numbers is a good example of a set of five different numbers whose mean is 290
