Please solve all questions and explain how to solve

Q1: How long will it take $500 to double if it earns 12%? (2 Marks) Q2: you borrow $230,000, the annual loan payments are $20,430 for 30 years, what interest rate are you being charged? (3 Marks) Q3: Sam will retire in 30 years. This year he wants to fund an amount of 20,000 to become available in 30 years. How much does he have to deposit into a pension plan earning 7% semiannually? (3 Marks) Q4: The NSF promises a monthly 0.85% return if you deposit 200 per month for 16 years. What amount will be accumulated after those 16 years? (3 Marks) Q5: Adam bought a house he estimates that the renewed cost for this house is 25,000 after 30 years. To cover these costs, he intends to save an equal amount of money at the end of each year, earning7% annual interest rate. How much is such a yearly annuity? (4 Marks) Q6: A company's net income after tax was $400,000 for its most recent year. The company's income statement included Tax Expense of $140,000 and Interest Expense of $60,000. At the beginning of the year the company's stockholders' equity was $1,900,000 and at the end of the year it was $2,100,000. What is the times interest earned for the company