please answer question 4

Single sums 1. calculating future values Sum today (PV) interest rate (I/Y) $1500 6% per year $1500 6% per year $2500 10% per year $2500 10% per year length of time (N) 7 years 7 years 20 years compounding annual semi-annual annual quarterly 20 years 2. calculating present values length of time (N) Future sum (FV) $7500 $7500 $500 $500 interest rate (l/Y) 8% per year 8% per year 18% per year 18% per year 5 years 5 years 20 years 20 years compounding annual semi-annual annual monthly 3. calculating interest rates (rates of return) length of time (N) Sum today (PV) $700 $950 future sum (FV) $1300 $1800 15 years 8 years compounding annual semi-annual 4. calculating the number of periods Sum today (PV) $4000 $38,650 future sum (FY) $7500 $213,380 interest rate (1/Y) 12% per year 10% per year compounding monthly annual