Answer: The required lifetime value is 11.27.
Step-by-step explanation:
Since we have given that
Mean value = 11 hours
Standard deviation = 1 hour
The total lifetime of all batteries in a package exceeds that value for only 5% of all packages.
So, α = 0.95, z= 1.645
n = 9
So, the lifetime value would be
Hence, the required lifetime value is 11.27.
An airplane is flying at a height of 5 kilometers above the ground. The distance along the ground from the airplane to the airport is 7 kilometers. What is the angle of depression from the airplane to the airport? (Write the answer to the nearest degree.)
✞ Step 1 ✞: Identify what is asked in the problem.
❒ The angle of depression from the airplane to the airport.
✞ Step 2 ✞: Use appropriate trigonometric ratio to solve the problem.
❒ Since the two legs of the right triangle are part of the problem, hence we use tangent ratio:
✞ Step 3 ✞: Solution and interpretation.
Hence, the angle of depression from the airplane to the airport is approximately 36°.