Tanner is three years younger than his sister, lexi. the sum of the siblings age is thirty three

Tanner: 15

Lexy: 18

Step-by-step explanation:

Tanner's age: r

Lexy's age: y

r + y = 33

r + 3 = y

If you substitute y into the first equation, you get:

r + r + 3 = 33

2r = 30

r = 15

Tanner's age is 15 years old.

Lexy's age is 15 + 3 = 18 years old.