(a) John, aged 70, has a house worth $500,000. He intends to borrow $100,000 as a lump sum. If the i

(a) John, aged 70, has a house worth $500,000. He intends to borrow $100,000 as a lump sum. If the interest rate is 10% p.a. payable annually (i=10%), and house prices increase by 3% p.a. (f = 3%), what is the percentage equity in 15 years?