I feel that i am not fairly treated

Why when i have problem, i turn to my father he ask me to learn to find solution myself, but when my sis got same problem, he help him out.

Yes i am jealous but i also felt that i am mistreated!!!
Why when i want to buy a PC, my father will ask me go search myself and see what price in the market that is offering. While my sis want to get a PC he ask me to help her out?
Not to say i don't take care of my sis. But this is not the first time it has happen.
Many times!!! She will always find excuse saying that she don't know and solution will be presented in front of her.
What about me??? Whenever i face a problem, i have to go learn myself how to deal with it. Eg. when my PC is down, i have to go take up course to learn how to fix it.
When my sis's PC got problem, she will go to my father and my father will look onto me...and the signal is send indirectly to me.
For things as simple as format the PC she also cannot do it herself!!! Just insert the CD into it and press few button also need me do for her. Not that i have not tried to teach her. She just don't want to learn.

Another case was the cart tinting, i went for tinting the car and paid myself even though i ask for money to do it from my dad. But when my sis get her car, she get it tinted and paid by my dad. And that was not even herself go tint it.
There are so many things that i felt so frustrated about it. Plus today, she want to go get some gadgets for her laptop, i even draw her the map to go there and there my father ask me to go with her to buy.
I mean what is it there for hr to go herself? Even if she get cheated by those ppl there is just money...nothing else. AT least she got the experience to deal with things by herself. Not always me helping her out. I got better things to do instead of babysitting her.