I was able to calculate the answers to every part except part D. I cant seem to find the solution.

Answer the following time value of money questions assuming the interest rate is 4 percent. a. What is the present value of $1,400 to be received in four years? b. What is the present value of $1,400 to be received in eight years? c. What will be the value in seven years of $11,900 invested today? d. How much would you pay for the right to receive $4,900 at the end of year 1, $3,900 at the end of year 2 , and $7,900 at the end of year 5 ? e. How long will it take for a $1,900 investment to double in value? f. What will be the value in 20 years of $1,700 invested at the end of each year for the next 20 years? Note: Round your answers to 2 decimal places