Please explain each question properly. Thanks

If $10,000 is borrowed now at 10% per year interest, determine the balance at the end of year 3 after payments of $3000 in year 2 and $3000 in year 3. Determine the difference in time it would take for money to double at an interest rate of 20% per year between simple and compound interest. Round your answer to the nearest year. If the sum of $7000 is deposited now, $5000 two years from now, and $2000 per year in years 4 through 8, determine the accumulated amount in year 8 if interest rate is 10% per year