Answer:
First statement is correct.
Step-by-step explanation:
If we add or subtract a constant to each term in a set:  Mean will increase or decrease by the same constant.  Standard Deviation will not change.
If we increase or decrease each term in a set by the same percent (multiply all terms by the constant):  Mean will increase or decrease by the same percent.  Standard Deviation will increase or decrease by the same percent.
For example:
Standard Deviation of a set: {1,1,4} will be the same as that of {5,5,8} as second set is obtained by adding 4 to each term of the first set.
That's because Standard Deviation shows how much variation there is from the mean. And when adding or subtracting a constant to each term we are shifting the mean of the set by this constant (mean will increase or decrease by the same constant) but the variation from the mean remains the same as all terms are also shifted by the same constant.
So according to this rule, statement (1) is sufficient to get new Standard Deviation, it'll be 30% less than the old.. As for statement (2) it's clearly insufficient as knowing mean gives us no help in getting new Standard Deviation.
 
        
             
        
        
        
Answer: -1/5
Step-by-step explanation:
14/20 - 81/90=
7/10-9/10=       ==> 10 is the GCF of 20 and 90
(7-9)/10=
-2/10=-1/5
 
        
                    
             
        
        
        
I believe the first question is 4 feet / 1 second and the second answer is 16 oz / 1 lb
        
             
        
        
        
Question 1:Look at the first attached image.
We want to solve for the height of the smaller building. Let's start by making a right triangle with angle of 15 degrees and adjacent side of 51 m.
Let's solve for the other leg. Multiply the tangent with 51 m to get the length of the other leg.


Now, subtract that from 207 to get the height of the smaller building.

That's your answer.
Question 2:
The angle of elevation is congruent to the angle of depression because they are alternate interior angles.
Thus, you can choose the 1st and 4th choices as your answer.
Question 3:Look at the second attached image.
Angle E is congruent to angle D for the same reasons mentioned in the last question.
We can create an equation.

Distributive property

Subtract both sides by 1 and 2x

Since E and D are congruent, just plug this value into one of the equations for E or D. You get 46.
The third choice is your answer. Hope this helps! :)
 
        
             
        
        
        
Answer:
The expected revenue of an airline ticket sold by this travel website is $408
Step-by-step explanation:
For the revenues per ticket we have;
airline A; 600
airline B; 360
For the probability of choosing the airlines we have;
airline A; 20% = 0.2
airline B; 80% = 0.8
Therefore, the expected revenue of an airline ticket sold by this travel website is;
600(0.2) + 360(0.8) = 408
Therefore, the expected revenue of an airline ticket sold by this travel website is $408