Let "x" represent the age of Brian.
Andrew is elder than Brian by 2 years, we can symbolize his age as "x+2"
Frank is twice as old as Andrew, we can symbolize his age as "2(x+2)"
Sarah has half the age of Brian's, we can symbolize her age as "x/2"
Frank ans Sarah's ages differ by 40 years, we can symbolize this as:
Solve the term is parenthesis
x=24 years
Andrew's age is
Andrew is 26 years old
Answer:
The student who weighted the rock 5 times has a 95% confidence interval of (25.2, 29.1) which is guaranteed to be more wider (less precise) than the other student who weighted the rock 20 times.
Step-by-step explanation:
What is Confidence Interval?
The confidence interval represents an interval that we can guarantee that the target variable will be within this interval for a given confidence level.
The confidence interval is given by
Where is the mean weight
is the standard deviation
is the critical value from t-table and n is the sample size.
The term is known as margin of error.
As the sample size is decreased the corresponding margin of error increases which results in wider confidence interval which means smaller precision.
The student who weighted the rock 5 times has a 95% confidence interval of (25.2, 29.1) which is guaranteed to be more wider (less precise) than the other student who weighted the rock 20 times.
We can say with 95% confidence that the true mean weight of the rock is within the interval of (25.2, 29.1).
Answer:
31
Step-by-step explanation:
Given
x² + 5x - 3 = 0
with a = 1, b = 5, c= - 3 , then
sum of roots x₁ + x₂ = - = -
= - 5
product of roots = =
= - 3
Now
(x₁ + x₂)² = x₁² + 2x₁x₂ + x₂² , that is
(- 5)² = x₁² + 2(- 3) + x₂²
25 = x₁² - 6 + x₂² ( add 6 to both sides ), then
x₁² + x₂² = 31