Hope this helps
Answer :
Percentage increase = (279 - 180)/180 x 100% = 55%
Answer: The average was 9 years old find the average age of both groups is 10 years old.
Step-by-step explanation:
Formula foe average : 
Given : The first group of students consists of 10 and their average age was 13 years old.
i.e.
(1)
The next group consisted of 30 students and their average was 9 years old.
i.e.
(2)
Then from (1) and (2) , the sum of both groups (first group and next group )students = 130+270 =400
Combined students of both groups (first and next group )= 10+30=40
Now , the average of both groups =

Hence, the average was 9 years old find the average age of both groups is 10 years old.
90 = (20)(x)
so you have to solve for x
90/.20 =450
answer is 450
Supposing the line graphed is y = 2x + 3, the equation of the different line is:
y = 4x + 3.
<h3>What is a linear function?</h3>
A linear function is modeled by:

In which:
- m is the slope, which is the rate of change, that is, by how much y changes when x changes by 1.
- b is the y-intercept, which is the value of y when x = 0.
In this problem, the equation is:
y = 2x + 3
Hence, the slope is 2 and the y-intercept is 3. For the new line, we want to:
- Double the slope, hence m = 4.
- Keep the same y-intercept, hence b = 3.
Then, the equation of the different line is:
y = 4x + 3.
You can learn more about the equation of a line at brainly.com/question/24685547