Researchers have found that after 25 years of age the average size of the pupil in a

person's eye decreases. The relationship between pupil diameter d (in millimeters) and age a (in years) can be modeled by

d=-2.1158 loge a+13.669 What is the average diameter of a pupil for a person 25 years old? 50 years old? Explain how you got your

answer.

At 25 = 6.8612mm

At 50 years = 5.422mm

Step-by-step explanation:

Equation,

d = 2.115Logₑa + 13.669

d = diameter of the pupil

a = number of years

Note : Logₑa = In a (check logarithmic rule)

d = 2.115Ina + 13.669

1. At 25 years,

d = - 2.115In25 + 13.669

d = - 2.115 * 3.2188 + 13.669

d = - 6.807762 + 13.669

d = 6.8612mm

At 25 years, the pupil shrinks by 6.86mm

2. At 50 years,

d = - 2.1158In50 + 13.669

d = - 2.1158 * 3.912 + 13.669

d = - 8.2770 + 13.699

d = 5.422mm

At 50 years, the pupil shirks by 5.422mm

To save this question, I had to plug in the values into the equation.

Solving for Logₑa might be difficult, so instead I used Inx which is the same thing. Afterwards, i substituted in the values and solve the equation for each years.