Eating restaurant foods

Q: It is common that for a person to achieve taqwa and progress on the pathway towards Allah Ta'ala, a person is advised to stay away from eating 'out' food. My question is, which aspect about "eating out food" makes it doubtful and should keep us away from it.

Wearing a Taweez

Q: 

1. Is taweez shirk?

2. Is it proven that a person can wear a taweez as protection knowing that Allah is the protector.

3. Will reading 7 times surah alam nashra help in exams? 

Classmates taking pictures of an exam paper from the teacher's laptop

Q: In our class some boys took an exam paper from our teachers laptop when he was out and they took pictures of it and maybe that is the same paper which the teacher is going to give us for the final exam. They did a wrong thing. I didn't have the courage to stop them. What should I do now? If I complain then all the boys will be saying bad words to me and they will mock me etc. But I dont need sin. And maybe if they dont get that paper then they will fail and maybe need to repeat the whole year (so much time and money will go to waste waste). What should I do? 

Investing in a company that is partnered with a company that deals in haraam

Q: I had a question regarding finance in islam, specifically investing in cryptocurrencies. I understand that it is only halal to invest in companies that do not deal with any haram acts such as interest or alcohol. However, I was curious to know, if company A, for example, is completely halal in its goals but is partnered with company B that is not halal such as a banking company, is it still halal to invest in company A?

I had a friend call a local sheikh who stated that it is halal to invest in company A since the goal of the company itself, for example to build an education platform, is completely halal even though company A is partnered with company B that is not halal. I just wanted to verify this information with another sheikh to put my mind at peace since I do still have some small amount of doubt.