Trick question:

if you are 10 years of age and your sister is half your age how old would she be when you are 100 years old.

a. 95

b. 50

c. 90

d. 55

When you are 10 years ,your sister will be 10/2 = 5 years

10 - 5 = 5
Your sister is 5 years younger to you

After 90 years your age will be 100 years.
After 90 years your sister's age will be 5+90 = 95 years

Correct option A

Hope This Helps You!