What is the FV of a $20,000 lump sum for 4 years at 4% annual interest?

What is the PV of a $15,000 lump sum receieved in 10 years at 2% annual interest ?

If you invest $10,000 today and expect to receive $50,000 in 15 years, what is the expected annual interest rate?

If you invest $1,000 today at an 8% interest rate, how long would it take to reach a value of $2,000?

What is the FV of a 2,400 ordinary annuity for 20 years ar 6% annual interest rate ?