Let x the age of John
Amy's age = x + 9
from question, we get,
John's age + Amy's age = 23
x+(x+9)= 23
=> x + x + 9 = 23
=> 2x = 23 - 9
=> x = 14/2
=> x = 7
Maximum area of the rectangle is 
<u>Explanation:</u>
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Considering the dimensions to be in cm

Putting the value of x = 3

Therefore, maximum area of the rectangle is 
Answer:
0.21
Step-by-step explanation: edge
Answer:
The coefficient of correlation does not change.
Step-by-step explanation:
We are given the following in the question:
The daily intake food is measured in ounces.
The body weight is measured in pounds.
Correlation between food intake and body weight = 0.80
Properties of correlation:
- Correlation is a technique that help us to find or define a relationship between two variables.
- It is a measure of linear relationship between two quantities.
- The correlation between two variables is not effected by the units of the variable.
- Even if the variable of the explanatory variable or the response variable changes, the correlation does not not change and remains same.
Conclusion:
A shift in units from ounces to grams and from pounds to kilogram does not change the value of coefficient of correlation.