In seven years, Huang will be two times as old as he was last year. How old is he now?

5 years old

8 years old

9 years old

14 years old

We can represent the age he is 'now' with the variable n

we can represent "in seven years" as (n + 7)

and

represent "last year" as (n - 1)

so

"in seven years, huang will be two times as old as he was last year"

would translate to

(n + 7) = 2 (n - 1)

to solve for n

first distribute the 2

n + 7 = 2n - 2

subtract n from both sides

7 = n - 2

add 2 to both sides

9 = n

therefore

n = 9

so Huang is currently 9 years old (C)