Answer:
Option (A) 0.40951
Step-by-step explanation:
We are given the following information in the question:
P(target) = 0.90
Let the random variable X represent the number of times he hits ring of the target with a shot of the arrow.
The probability distribution of X is
x: 0 1 2 3 4 5
P(x): 0.00001 0.00045 0.00810 0.07290 0.32805 0.59049
The mean of discrete probability distribution is given by:

Now, we have to evaluate

Option (A) 0.40951 t is the probability that the number of times Luke will hit the inner ring of the target out of the 5 attempts is less than the mean of X.
The equation is:
20,000 * e^(0.15 t) = 28,000
e^( 0.15 t ) = 28,000 : 20,000
e^( 0.15 t ) = 1.4
0.15 t = ln 1.4
0.15 t = 0.3365
t = 0.3365 : 0.15
t = 2.24 ≈ 2
Answer:
A ) 2 years.
How are we supposed to answer that question. When we can't see the segments?