help with both questions 2.35 & 2.39

2.39 If the value of Jane's retirement portfolio in creased from S170,000 to S813,000 over a 15-year period, with no deposits made to the account over that period, what annual rate of return did she make? 2.35 Determine the difference in the present worth val ues of the following two commodity contracts at an interest rate of 8% per year. Contract 1 has a cost of S10,000 in year 1; costs will escalate at a rate of 4% per year for 10 years. Contract 2 has the same cost in year 1, but costs will escalate at 6% per year for 11 years