Beginning of Esha time

Q: I read that Maghrib prayer time ends when the redness in the sky goes away. Also I read that it ends half an hour before Isha Azan. Which one is true? Half an hour before Isha azan I feel the sky becomes darker. Can I still pray Maghrib or should I mention as qadha namaz? As I'm a working woman and gets little late to reach home and can't pray in van.

Travelling with a non-mahram

Q:

1. Is it permissible for a woman to sit in the passenger seat of a car which is being driven by a non mahram man?

2. Is it permissible for a woman to sit behind a non mahram man on a motorbike or bicycle?

3. Is it permissible for a non mahram man and a non mahram woman to sit next to each other?

Marking items at a higher price due to people asking for discounts

Q: Someone owns a shop. Because people often ask for discounts, they mark the items higher, so when people ask for discounts, they give it and still get their desired profit. 

Eg. He wants a profit of R50 for a R100 item. However, knowing that people will ask for a discount, he marks the item as R200. So when people ask for a R50 discount, he gives it to them and still gets his desired profit. Is this permissible in Shari'ah or is that money haraam?

Planting a fig tree

Q: My husband and I recently planted a fig tree in our yard and my mum has advised us to remove it. She said that jinns are known to live on the fig tree more frequently than other trees. Please can you advise me if there is any truth to this and if yes please refer me to the hadith or section in the Quran.