Question 7 A payment of R150 000 due in 30 years' time is purchased from a company by means of level monthly payments. For the first 10 years 8% of each payment is taken by the company as expenses, with this charge reducing to 3% for each payment made after the end of year 10. Interest is calculated at 11% p.a. compounded half-yearly for the first 15 years and 14% p.a. effective thereafter. If the first payment is in two years' time, and the last payment is made one month before the payment of R150 000, find the monthly payment by drawing up an equation of value at time 30. [10 Marks]