Answer:
John is 20 years old.
Step-by-step explanation:
Given the second mean is 18, it is equal to the first mean age plus John's unknown age. The sum is also divided by 2 because there are 2 values in the sum (1. John's age and 2. the mean, 16 yrs old).
Set up an equation: [tex]\frac{x+16}{2}=18[/tex]
multiply both sides by 2: [tex]x+16=36[/tex]
simplify: [tex]x=20[/tex]
