Answer: 6 years old.
Step-by-step explanation:
For this exercise let "x" represents your present age.
According to the information provided in the exercise, you know that In three years, Chad will be three times your present age.
Then, your age in three years can be represented with the following expression:
Knowing at that time Chad's age will be three times yours and you will be half as old as old as Chad, you can write the following equation to represent this situation:
Therefore, the final step is to solve for "x" in order to find its value.
You get that this is:
The answer is A sorry your out of time
Standard deviation is calculated by
1. calculate mean, m
2. calculate deviation of EACH entry of data set from the mean, i.e.
d=(x-m)
3. calculate mean of square of deviations (d^2)/n to get variance,v
4. take square-root of variance to get standard deviation.
For example,
To find the standard deviation of data set {3,7,8}
1. mean=(3+7+8)/3=6
2. deviations, di={3-6,7-6,8-6}={-3,1,2}
3. squares of deviations, di^2={9,1,4}
4. mean of squares of deviations=(9+1+4)/3=14/3
Standard deviation=sqrt(14/3)=2.16
For the given data set, if you follow the above steps, you would get
sum=400
mean=400/9
variance (mean square of deviations)=8246/81
standard deviation=sqrt(8246/81)=sqrt(8246)/9
Check the picture below.
now, looking at the picture's scaling, from the lower-left-corner up to 20 is 5 squares, the rectangles you see in the picture are 40 units each, namely 10 squares. Every square is 4 units, it goes up 12 squares, namely 48 units, and goes to the right by 30 squares plus 4 more, 34 squares, that's 136 units.
well, if we were to make a triangle for the slope, check the picture, it'd look like that.
Why is the slope negative? well, because is going down from left to right.
Okay, so let's find the average
People with 92: 18(92)
People with 84: 12(84)
1656 + 1008 = 2664
So then we divide by 30
2664 / 30: 88.8
The average is a score of 88.8
