Respuesta :

Answer:

Sam is 7 and 1/2 years old.

Step-by-step explanation:

Let Sam be x years old. Then we have the equation:

2x + 6 = 21

2x = 21-6 = 15

x = 7.5.

7½yrs

Step-by-step explanation:

Sam = x

Oliver = 6 + 2x

Sam = (21-6) ÷2

Sam=15÷2

Sam=7½yrs