Interest money

Using interest money to fix potholes and to pay off interest of a bond

Q: I wanted to find out about the following to questions regarding interest.

1. Is it permissible to hire out people with interest money to repair potholes which the government supposed to do and are not doing so. Would it affect the maslah if the person who gave the interest money to repair the roads is also using the roads and taking benefit from this interest money?

2.Can a person use interest money to pay off the interest of a bond?

Taking an interest bearing loan to save oneself from paying tax

Q: A person deals mostly in cash and does not deposit in the bank in order to avoid showing too much income and paying exorbitant amounts of tax to the government. However, he cannot purchase large items such as properties and cars etc as it has to be done with "legal" money.

The only way out for him will be to take a loan from the bank in order for his purchases to be recognized legally. He will offset the interest payable with the interest he receives from his bank account.

Can this be a valid excuse to enter into an interest bearing loan with the bank?