Hamza and Khalifa have been best friends since high school. They have recently learnt about the concept of superannuation, and are now both planning their retirement early. Both Hamza and Khalifa would like to have $2 million at the age of 60, each, when they retire. Hamza plans on depositing equal annual amounts into his superannuation fund on each birthday, starting at the age of 21, and ending at the age of 60 (that includes a deposit on the 60th birthday as well). Khalifa, however, starts making deposits into his superannuation fund on his 30th birthday and plans to deposit equal annual amounts on each birthday until he turns 60 (that includes a deposit on the 60th birthday as well). If the investment funds earn 10% per year, calculate the amounts the Hamza and Khalifa respectively will have to save each year to meet their retirement goals. Comment on the difference.