IIM Ahmedabad - Indian Institute of Management

A good percentage in 10th and 12th are:
50% and above in graduation,
99 percentile in CAT (general) ,
89 percentile in CAT (SC),
and 85 percentile in CAT (ST).
Then you will also have to convert your calls.

You can not join IIMA without appearing for CAT examination.

For IIMs it is totally impossible. Look these institute are the top institutes in our country. If you really want to study here than you will have to strive for it. People here have secured admission for their merit not their money. So why not invest some amount in your preparation, so that you can secure a seat here.

No it's not possible without an entrance test. If you really want to take admission in an IIM or any other reputed institution for that matter, you need to give an entrance test.
Hope that helps.

Yes they help a lot. Especially you need to have a 50% or more in graduation.

IIM Indore does not offer any undergraduate course.

It doesn't. In fact, a majority of the students at IIM-A (or any other IIM for that matter) are from a technical background with majority being from an engineering background. So, you need not worry about being from a technical background.

You will definitely get a good college, if you are ambitious enough. You can prepare for CAT exam with determination. You should score an excellent percentile, then you can get a call from IIM – A. You can prepare yourself for WAT/ PI and impress the panel.
Best of luck.

The candidate should have a good percentile, i.e. around 99 percentile. You must have a good academic score. Also, you must prepare yourself well for GD/PI if you get a call. If you are confident and honest then IIM-A is waiting for you.
If you are working then you have another feather on your cap, i.e. you work experience. So, boost up yourself and prepare well.