Respuesta :

the boy is 15 because twice the age of his sister is 12, then you add the three years to it and get 15
What u do is, take the sister's age, then multiply it by 2 because the boy is 3 years older than TWICE his sister's age. His sister is 6, so 6x2=12, and he is 3 years older, so 6x2+3=15