Respuesta :
If the boy has 10, and his sister has 2 1/2 times as many as him, you would first multiply 10 times 2 to get 20. After that you would automatically 1/2 of 10 is 5, which would bring you to the conclusion that his sister has 25 cookies. Thus, you answer is 25 cookies.
Answer:
25
Step-by-step explanation:
10×2.5=25
and heres some other random stuff so brainly will let me tell you this