To find an area of a triangle you do 1/2 x base x height.
Answer : 0.0129
Step-by-step explanation:
Given : Based on FAA estimates the average age of the fleets of the 10 largest U.S. commercial passenger carriers is
years and standard deviation is
years.
Sample size : 
Let X be the random variable that represents the age of fleets.
We assume that the ages of the fleets of the 10 largest U.S. commercial passenger carriers are normally distributed.
For z-score,

For x=14

By using the standard normal distribution table , the probability that the average age of these 40 airplanes is at least 14 years old will be :-

Hence, the required probability = 0.0129
F(x)= -8x²
f(-3)= -8* (-3)²
f(-3)= -8 * 9
f(-3)= -72
U autocorrect this as thsi too!? Omg