بسم الله الرحمن الرحيم
If there are only 8 brothers and 3 sisters among the heir of any deceased person and he/she has left 10 lakh rupees then it shall be divided as per the below mentioned method:
Each brother shall get 105363.15 while each sister shall get 52631.57 as a brother/son gets just double of what a sister/daughter gets.
Allah knows Best!
Darul Uloom Deoband