Stella Lam (Stella) recently joins the workforce, and her starting salary is $3,500 per month. The CPF contribution rate (both employer and employee) for her age group is 37%, and this is allocated as follows:

Ordinary account = 60%

Medisave account = 22%

Special account = 18%

The interest rate paid by CPF Board on members ordinary account is 2.5% per annum, compounded monthly. As Stella intends to settle down with her fianc, she needs to set aside $25,000 in her ordinary account to buy a 4-room HDB apartment.

Calculate how long Stella needs to work in order to afford the HDB apartment and examine how she can possibly accelerate this process.