Terry is n years old. Dennis is 2n + 5 years old. If Terry is 8 years old, how old is Dennis?

To find Dennis’s age, we can substitute Terry’s age into the equation given for Dennis’s age.

1. Terry’s age (n): 8 years
2. Dennis’s age formula: 2n + 5

Now, plug in Terry’s age (n = 8) into the formula for Dennis:

[

Dennis’s , age = 2(8) + 5

]

[

= 16 + 5

]

[

= 21 , years

]

So, Dennis is 21 years old. The correct answer is A 21.